Following Diagne, we take translation to be less about accomplishing a task (i.e., translating Zulu to English) and more about seeing the opportunities to move between languages—in this case, our languages are the different microworlds of multiplication. We insist on the fact that what is being translated is not a Platonic concept of multiplication, but ways of thinking and acting and feeling. If Grasplify is the world students first encounter, the experience is not a grounding to multiplication; rather, Grasplify provides a locality that involves certain ways of speaking and moving, of seeing and noticing. Grasplify has its own cosmology in which students touch and gesture, in which pips and pods appear on the screen, as well as symbols and expressions. When they move to Zaplify, they are not initially aware of the resonance with Grasplify; rather, Zaplify is a new locality with its own immersiveness. But the resonance emerges through their touch, their perception of the lines, pods, and symbols, and their follow-up interactions.
To convey the fullness of what we intend by “thinking and acting and feeling”, we have selected three episodes from the same pair of students that feature significant translations between Grasplify and Zaplify. Drawing on the same pair of students enables us to provide the readers with a sense of how their multiplicative thinking evolved over time. We present these first in the subsection “Three cases of translation with Ian and Fabian”. In the next subsection, “Patterns of translation”, we focus on the broader patterns of translation that we observed across the four pairs of students during the interviews. We also highlight some of the untranslatables we noticed.
5.1. Three Cases of Translation with Ian and Fabian
Case 1: Translating the identification of units.
In answering the button question in Grasplify, Ian touches five pips simultaneously with his left hand and then eight pods sequentially with his right hand. He then counts the number of pips in a pod by pointing with his right hand and holding out all five fingers on his left hand at once and then using his fingers as units of five, skip counting by 5 s (he lifted all five fingers and then three more) to obtain 40. The multiplicative expression 5 × 8 is at the top of the screen but the product is not showing.
The interviewer asks the pair to use Zaplify to answer the same question. Ian touches five horizontal lines with his left hand and sequentially touches eight vertical lines with his right hand. He then counts the number of intersection points along the bottom (there are eight). He counts the number of intersections along a vertical, obtaining five. The interviewer says, “So there’s five times eight”. Ian then says, “You can just count the buttons”. Ian counts along the bottom line, one by one to eight; Fabian counts along the vertical to five, and then Ian goes to the top row and counts by 5 s, not on his fingers this time, but by pointing and counting the buttons along the top row. He says “40” and seems satisfied, perhaps because it matched the answer from Grasplify.
In the shift from Grasplify to Zaplify, several aspects relevant to translation occurred. First, Ian used the same hand gestures, touching five times simultaneously with his left hand and then eight times sequentially with his right hand. The screen actions therefore translated directly. Second, in both cases, the pair also sought to find the value of the product, which they did by skip-counting. However, whereas the number of pods was not explicitly named in Grasplify, it was in Zaplify, where the pair counted both the number of horizontal lines and the number of vertical lines. The status of the factors and therefore the way of finding the product did not translate directly. Specifically, the units of five in Grasplify seem more evident than in Zaplify. We note that the problem context of buttons becomes relevant in Zaplify, since Ian evoked having to count the number of “buttons”, while pointing to the points of intersection. This observation highlights the fact that the pair was engaged in a double translation, from word problem to Grasplify to Zaplify.
Case 2: Translating between points and lines.
While working on the tomato problem, Ian immediately chooses Grasplify and placed five fingers on the left and then touched two fingers at a time, five times, configuring the 10 pods into five rows of two pods. He then reads the problem again, touches once more with two fingers to make 12 pods in total. Fabian reads the question out loud. They both start to drag pods to the trash and accidentally lift all the pip-fingers, so they have to start again. Ian then makes five pips and 10 pods, drags one to the trash (
Figure 3a). Fabian counts the number of pods. Ian presses the array button momentarily and releases it. There is a silence, then the interviewer asks, “Can you tell me what’s going on?” Fabian says, “there are five rows”. Ian then touches the array button and holds it for 34 s (
Figure 3b). The interviewer asks, “how many rows are there? If you see this as a row”, pointing at the top row in the array. Fabian says, “If you were to see this as a row, five. Wait”. Ian says “nine”. Fabian starts to count the rows, but Ian repeats “nine” and Fabian says “yeah nine”. When asked if there was a reason for their choice of the Grasplify world, Ian says, “because you can make it in a row unlike the other one”. The interviewer then suggests they try the problem in Zaplify.
In Zaplify, Ian created five horizontal lines with his left hand and then nine vertical lines with his right hand. The interviewer then asked, “Ok, what do you think of that, what would your interpretation be, of nine rows of five?” Ian counted exactly like he had done with the buttons problem, along the bottom from left to right by pointing to each intersection point. He then counted the vertical lines and quickly he said, “Five. Yeah, there’s nine rows by five”. Fabian said, “Yeah there’s five” and he moved his finger up the vertical line and then used a chopping gesture (
Figure 4a) above the bottom row, while saying “there are nine”. The interviewer then commented, “these look like rows [pointing to the horizontal lines], right? Do you think this microworld is better?” Ian said, “probably” and then elaborated, “because the rows are actually like even rows (gesturing along the horizontal row), unlike the other (fades off). It’s like automatically even, it’s faster”, moving his right hand horizontally over the row back and forth. Fabian said something about Grasplify, of which most was inaudible, but he tapped his finger three times on the table (
Figure 4b). Ian continued, “In the other one [Grasplify], you have to count each one in the little [trails off, but referring to the pods]”.
In Grasplify, modelling the tomato problem took several tries. The making of five pips (using a simultaneous left-hand tap) was immediate, but making the pods involved some trial and error—they first made 10 pods, then 12, and then finally 9. The mention of rows in the problem seemed to make Ian want to create rows of pods. When the pair shifted to the array view, this changed their perception of the rows, which they were first seeing as the columns of the array. The translation from the word problem to Grasplify was therefore not transparent. However, when the pair shifted to Zaplify, Ian quickly made five horizontal lines and then nine vertical lines. He noticed that Zaplify produces the horizontal lines, which are the rows of the problem, “automatically”, which is indeed “faster”. Whereas Grasplify drew Ian’s attention to the tomatoes, through the making of pips, Zaplify seemed to draw attention towards the rows, allowing Ian to coordinate the horizontal lines on the screen with the rows of the problem.
When describing Zaplify, the pair started to make gestures that were specific to the rows and columns, including chopping and waving gestures that not only express the rows and columns, but also seem to evoke these individual rows and columns as units. Whereas in Grasplify, the unit is a pod, which as Fabian suggested, through the tapping gesture, that you count, in Zaplify, the unit is a line, which includes the relevant number of intersection points. In other words, the unit, which was a count in Grasplify, translates into a chopping or waving gesture in Zaplify.
Doing the problem in each microworld highlights a different aspect of it, as well as a different object in the microworld. This aligns with Diagne’s idea of seeing the opportunities in both worlds, so that translating involves switching between tomatoes and rows. In this case, the translation is the awareness of the various features in the two worlds. In Ian’s words, in Grasplify, “you have to count each one inside the pods”, while in Zaplify, “the rows are actual rows”. The two microworlds have different local contexts and suggests to Ian that in one the focus is on tomatoes as objects, and in the other, rows are the dominant objects. These can be seen as two ways of planting tomatoes; one can dig the troughs for the seeds and then put in the seeds later, in which case the focus will be on the trough, or one can count the seeds and sprinkle them according to how many seeds there are.
Case 3: Translating between Grasplify arrays and Zaplify.
In the previous two episodes, we examined the translations that occurred when Ian and Fabian went from one world to the other as they modelled a word problem. In this episode, we want to focus on an episode in which the interviewer asked the pair to directly compare elements of each world. This provides insight both into how some visual element-to-element translations are more challenging and how provoking these forms of translation require direct and explicit questioning.
After completing the second problem, the interviewer asks Ian and Fabian to explain how the rows and columns of Zaplify related to the pips and pods of Grasplify. They say that the pips were the intersection points and the pods are the rows. They also circle the rows in Zaplify to demonstrate how they correspond to the pods containing pips in Grasplify. When asked where the rows in Zaplify could be seen in Grasplify, Ian and Fabian make four pips and five pods, then press the array button. They then draw horizontal and vertical lines between the pips and create additional dots where the lines intersected (
Figure 5a). The interviewer prompt the students again, “can you think of these discs as the orange connectors?” The students then draw vertical lines that go through the pips, but the horizontal lines do not (
Figure 5b). The interviewer directs their attention to the number of horizontal lines drawn compared to the number of rows of pips in the array and asks if the two should line up. Eventually, the students draw five horizontal lines that go through the five rows of pips (
Figure 5c). When asked to explain how their annotations helped to make it look like Zaplify, Ian says, “in between the lines, there are dots and that’s how you can tell how many dots there are”.
This episode highlights how non-trivial the visual translation across the two microworlds was for the students. They were fluent when it came to translating a word problem containing two factors from one world to the other. However, the visual signs (pips, pods, intersection points, and vertical and horizontal lines) seemed to be specific to each world. It was only with much probing by the interviewer that the horizontal and vertical lines and intersections of Zaplify could be seen as annotation lines going through the array of pips in Grasplify.
5.2. Patterns of Translations
While the previous section had focused on specific cases in which we noticed interesting or unusual instances of translation with Ian and Fabian, this section provides some overall patterns across the four pairs of students, highlighting common translations, as well as untranslatables. We begin with the word problems and discuss how students went about enacting them, noting which microworld the students chose to use first and what they did and said when they enacted the problem in the other microworld.
5.2.1. Button Problem
For the button problem, two pairs chose to first solve it in Grasplify, and two pairs chose Zaplify first. Although they did not all start with the same microworld, all the pairs started by tapping five fingers on the left (to make pips in Grasplify and horizontal lines in Zaplify), then tapping eight fingers on the right or the bottom (to create pods in Grasplify and vertical lines in Zaplify). These finger placements and the sequential order are aligned to the context of the problem of having five buttons in each heap and making eight heaps. Thus, there is a translation from the problem context to where the students placed their fingers and in which order they placed them. Of the three pairs that also solved the problem in the other microworld, two pairs also started by tapping five fingers on the left, then tapping eight fingers on the right or the bottom. We can therefore say that these two pairs haptically translated the action, both in terms of the sequential order (5 and then 8) and in terms of the position (left, then right/bottom) from one microworld to the other. This is interesting because the problem could also have been solved in Zaplify by placing eight fingers along the left side and five along the right or bottom. In other words, sequential touching translates even when order does not matter.
In one case, the haptic translation pertained also to the way the factors were created. Bert and Wayne made 5 × 8 in Zaplify by first making horizontal lines followed by five vertical lines, followed by another three vertical lines (
Figure 6a). They tried to find the product, first saying 13, then 80, and then finally, 40. When asked if they can do the problem in Grasplify, Bert put five fingers on the left, Wayne put five and then three fingers on the right (
Figure 6b), exactly like he had done in Zaplify. The breaking down of eight into five and three may feel haptically more natural than tapping eight fingers all at once.
The other pair of students who solved the problem in a second world, going from Zaplify to Grasplify, did not translate their actions. Before using Zaplify, Leo had stated the product (40) out loud. While he was doing that, Rob had already opened Zaplify and had placed five fingers on the left (refer to
Figure 7a, where the fingers are positioned horizontally rather than vertically). Leo pressed the lock button and made eight sequential taps on the bottom. When asked whether they could do the problem in Grasplify, Leo first placed five pip-fingers on the left side of the screen simultaneously (
Figure 7b), then using his right hand placed three more fingers on the left side, while Rob made five pods sequentially, thereby obtaining 8 × 5 (
Figure 7c). When asked how Grasplify shows the buttons and heaps, Leo explained that the heaps are on the right side and the buttons on the left, while re-making the product as five pips and eight pods.
The order and the placement of the fingers were initially reversed, when going from Zaplify to Grasplify, which suggests that the translation is not occurring haptically and is instead focused on the value of the factors. We note also that the Grasplify solution does not reflect the problem statement, which involves eight heaps of five buttons. When Leo re-made the product, however, he reversed the order again. It is therefore the problem statement itself that changed the translation. After Leo finished making the product, Rob remarked that Grasplify is better because it shows the groups more clearly than Zaplify. When asked if it is possible to see the groups in Zaplify, Leo said “no”. Rob changed to Zaplify, made 3 × 3, and then said that you cannot. But then Leo changed his mind, saying “in the vertical and the horizontal lines”, gesturing along each of the lines. They both agreed, however, that it is not as obvious. We see here Leo making a translation from the pods to the lines, but recognising the translation is not perfect.
5.2.2. Tomato Problem
For the tomato problem, again, the same two pairs first solved it in Grasplify and the other two pairs first solved it in Zaplify. Although they did not all start with the same world, three pairs started by making five taps (pips in Grasplify and horizontal lines in Zaplify), then nine taps (pods in Grasplify and vertical lines in Zaplify). In Grasplify, these finger placements and the sequential order are aligned to the context of the problem of having five tomatoes in each row and making nine rows, but in Zaplify, they do not reflect the context of the problem as there are five rows of nine tomatoes instead. Of the three pairs that also solved the problem in the other world, two pairs made the exact same tapping actions. Again, there was a haptic translation between the worlds both in terms of the sequential order (5 and then 9) and in terms of the position (left, then right/bottom).
Mandy and Tania proceeded differently. They started in Zaplify. Mandy made one vertical line first, then pressed the lock button. She created four more vertical lines sequentially, after which she created nine horizontal lines sequentially. But when the interviewer asked her to explain what she had done, she switched to Grasplify and said, “this is easier”. In Grasplify, Mandy made five pips simultaneously, then created pods sequentially, configuring them into four rows of two pods and then an additional pod underneath the four rows. She explained that the solution is 45 because the previous problem was 5 × 8 (for the button problem) and it was 40, so she would add 5 to 40. In this case, there was no haptic translation and interestingly a preference for using Grasplify, perhaps because it enabled the direct creation of objects (the pips, which could be interpreted as the tomatoes) whereas Zaplify only produces objects (the intersections) once there are both horizontal and vertical lines. Therefore, translated here are the tomatoes of the problem into the pips of Grasplify.
Indeed, when asked to explain what the pips and the pods represent, Mandy replied, “these dots (pointing at the pips) are the tomatoes, and these are the nine rows (pointing at the pods)”. The interviewer asked the pair to go back to Zaplify. Again, Mandy first created one vertical line and pressed the lock button. She then made four more vertical lines sequentially. The interviewer interrupted and asked, “What do the five vertical lines represent?” Mandy replied “tomatoes”. She then created nine horizontal lines. Although these actions are not the same as her actions in Grasplify, they are consistent with her initial attempt in Zaplify and also reflect the problem context of nine rows of tomatoes with five in each row. Thus, it seems that there is a translation from the problem context of nine rows (of tomatoes) to the nine horizontal lines and five tomatoes in each row to the five vertical lines.
When asked to explain where the rows and tomatoes are, initially she said, “like five here (using her index finger to swipe up and down vertically)”, then she hesitated and said, “no, five here (using her index finger to swipe left and right horizontally) and nine here (using her index and third finger to swipe up and down vertically). And the nine represents kind of like the rows (used her right hand to swipe left and right horizontally) and there will be five on each row”. Hence, in Grasplify, the units are seen as points, both pips and pods, while in Zaplify, the units seem to have been translated to lines, as implied from the switch Mandy made from a pointing to a swiping gesture.
For the last pair, when the interviewer read out the problem, Wayne said, “I just look at the numbers and times”. As soon as the interviewer said, “how many tomatoes”, Wayne answered 45. When asked which microworld they would use, they quickly selected Zaplify, with Wayne saying “there’s rows in this one”. Bert tapped three fingers on the side and the interviewer said, “I don’t see the tomatoes”. Bert placed three fingers on the bottom and said, “there are the tomatoes”, pointing to the intersection points. Bert said, “you get the tomatoes after a couple stages of plants”. Meanwhile, they added more lines on the screen, until there were eight columns and five rows. There is no comment on the fact that the problem talks about nine rows. The interviewer did not ask the boys to solve the problem in Grasplify, so there is little to say about translation between the microworlds. However, it is clear that there is a translation from the problem context of rows (of tomatoes) to the choice of Zaplify and that the tomatoes were translated into intersection points, with an awareness that these emerge after the creation of horizontal and vertical lines—Bert even introduced a new metaphor of “stage of plants” to describe the temporal emergence of the tomatoes/intersections. This can be seen as a creative translation that draws on the language of Zaplify to elaborate the context of the problem.
5.2.3. Combinatorics Problem
Finally, we discuss the combinatorics problem, which only two of the pairs attempted. Both started solving the problem without using TT and, when prompted, chose Grasplify. After hearing the problem, Leo immediately moved his hand as if he was about to use Grasplify, but pulled it back to touch the table, saying “I have one hoodie (extending one left-hand finger) and then I have like five sweatpants (putting his five right-hand fingers on the desk). And that one hoodie can go with five of them (moving his left-hand finger back and forth to each of the right fingers) so […] and then there are three other hoodies so you just do it with those (gesturing back and forth again)”.
When prompted to think about the same problem in either Grasplify or Zaplify, Leo chose Grasplify, which was already open. He created one pip, referring to it as one hoodie and then five pods, which he called the sweatpants (
Figure 8a). Similar to the gesture he made before, he moved his pip-finger back and forth, dragging the pip to each of the five pods and said, “you can pair one (pip) with each of them (pods)”. He created three more pips for a total of four and said, “and like you can do it four times to get twenty styles” (
Figure 8b).
The interviewer then asked them to do the problem in Zaplify. Leo said, “Okay, so you like have one of them (creating a single horizontal row, then touching the lock button) and then you have five (touching five times sequentially, making vertical lines, as in
Figure 9a)”. The interviewer said, “So this is one combo?”, pointing to an intersection. Leo answered, “Yeah, and you can see all the combos (gesturing along the row, back and forth, as in
Figure 9b, to all the red dots and then touching three more times on the horizontal). And you can see four, see, you can see all of the combos and it’s like (showing the lines too, as in
Figure 9c) so you know, which ones… [trails off]… so you know which pants go with which hoodies”. Leo emphasised the word “know”, highlighting his awareness that each intersection represents a specific combo. This explanation with his fingers, gestures, and words does not draw on the visual output of either Grasplify or Zaplify, but does draw on the haptics of using TT.
Leo solved the problem with his hands, then with Grasplify. In both cases, he used a back-and-forth, one-to-one matching gesture to connect the articles of clothing with each other. This dynamic gesture is analogous to taking a hoodie and moving it from one pair of sweatpants to the next to see which is the best combination. But there is a translation that occurs when moving to Zaplify. There is no one-to-one dynamic matching in Zaplify. Zaplify in this problem is less about getting dressed and more about laying out all the possibilities. This is impossible to do in real life, since you only have one green hoodie, so you cannot lay it down and pair it with all the different sweatpants at the same time. In this way, Zaplify does not have a real-life analogy in this problem. Rather, Zaplify presents a static expression of all the possibilities, which Leo acknowledged when he said, “so you know which pants go with which hoodies”. He drew upon the notion of lines, as seen in
Figure 9c, expressing that the lines are these links, which is no longer his one-to-one matching. Each horizontal line is a hoodie and each vertical line is a pair of sweatpants. This translation between one-to-one matching to an acknowledgement of all possibilities at once can be seen as a move from a unary relationship, where factors play different roles, to a Cartesian product relationship. In a Cartesian product, each number in one set is listed out with each number in another set, or, in this case, each line in the vertical is matched with each line in the horizontal.
When Bert and Wayne were presented with the problem, they were unsure how to proceed. The interviewer simplified the problem to two sweatpants and used strips of paper to represent the hoodies and sweatpants and also did a one-to-one matching gesture to pair each of the hoodies with one sweatpants. The pair proceeded to solve the problem (with two sweatpants) in Grasplify. They created two pips and five pods. When asked to explain what the pips and pods represent, Bert said, “We can literally match any of them like this”, while dragging one pod from the right to meet the two pips on the left (
Figure 10), which is similar to what Leo did. There is a translation from the interviewer’s one-to-one dynamic matching using strips of paper to the one-to-one matching of the pods (representing hoodies) to the pips (representing sweatpants) in Grasplify.
5.3. Follow-Up Questions
After working through the three questions, the interviewers explicitly asked the students to compare the pips and pods of Grasplify with the lines of Zaplify. For Bert and Wayne, the interviewer had created 4 × 3 in Grasplify and asked them to make the same product in Zaplify. They haptically translated, with Wayne making four horizontal lines and Bert making three vertical lines. When asked to explain how the lines in Zaplify are the same as the pips and pods in Grasplify, Bert replied, “well, it’s dots and groups”. Wayne added, “it just doesn’t have lines… wait, are those groups of four?” The interviewer replied, “yes, there are groups of four. So, are there groups here (referring to Zaplify)? Is there a way to see groups here?” Bert said, “well, ya, like if you draw circles around all of these… This is a group of three (circling gesture around the topmost row of 3 points)”. The interviewer asked, “are there any groups of four?”, to which Bert replied, “like this, (circling gesture around the leftmost column of 4 points, as outlined in a black frame in
Figure 11a)”. Wayne added, “like squares are groups of four (gesturing in a shape of square around 4 points forming a square, as in
Figure 11b)”.
Ian and Fabian were given the same situation, in which the interviewer made 4 × 3 in Grasplify and they were asked to describe where the pods are in Zaplify. Ian did a circling gesture around the topmost row of three points and responded, “here, the rows?” The interviewer asked, “but when I look here, I see three. And if I am looking for pods, how many are in a pod?” Both students replied “four”, and Ian quickly cleared the screen and created three horizontal lines and then four vertical lines. Then, he did the same circling gesture around the topmost row of four points and said “here” to illustrate where the four pods could be seen.
For Mandy and Tania, the interviewer created 4 × 6 in Grasplify and asked them to make the product in Zaplify. Tania created one vertical line, pressed the lock button, and then made three more vertical lines. She then made six horizontal lines. When asked to explain where the four pips are in Zaplify, Tania replied, “oh, here, (swiping gesture along the topmost row) … I mean, these things (swiping gesture up and down along the columns with index finger, as in
Figure 12a, first followed by similar swiping gesture with her hand, as in
Figure 12b, going from right to left)”, referring to the four vertical lines. And when explaining about the six pods, Mandy swiped from left to right along the bottom row and repeated the same gesture for the other five rows.
The way the students expressed pips and pods in Zaplify varied, although most pairs were more inclined to see the groups as rows rather than columns. Indeed, Ian and Fabian reset their screen in Zaplify, which had three rows and four columns, and made four rows and three columns, so they could circle four rows instead of four columns.
Thinking with Diagne’s idea of translation, which emphasises the values that are at play in different cultures and the effect these have on what is translated and how, we were especially attentive to preferences that the students articulated with respect to each microworld. These preferences were sometimes related to the problem itself, but other times to the appearance and the functionality of each world. For example, when introduced to the tomato problem, Rob and Leo already had Zaplify open. After listening to the problem, Rob changed to Grasplify. However, Leo said that “since the problem talks about rows and there are already rows in Zaplify, it would be easier to understand”. But they made five rows and nine columns, even though the problem states that there are nine rows. When asked whether they could do it in Grasplify, Rob said it would be easier. Leo made five pips simultaneously and Rob made nine pods sequentially. He said, “I don’t know, I just think it’s more helpful to see these [gesturing to the pods]”. Rob mentioned several times over the course of the interview that he preferred Grasplify for the way that it showed the pods, but It was particularly Interesting In this problem, which was explicitly about rows. We interpret his preference for Grasplify less in terms of whether it models the problem better than in terms of providing him with a better way of understanding the meaning of multiplication. In contrast, Leo mentioned his preference for Zaplify on two occasions. The second time, described in this paragraph, was related to understanding the problem. On the first time, which was for the button problem, Leo said that Zaplify was quicker and easier, because you can use the lock button and not have to hold a hand on the screen.
5.4. Untranslatables
During our interviews, we sometimes probed the students on their actions and choices. For example, Bert and Wayne had made 4 × 3 in Grasplify (
Figure 13a) and the interviewer asked, “So is that the only way you could do it?” Bert said, “Not really, you could switch them around”. The interviewer asked, “Can you show me what you mean?” They immediately made three pips and four pods (
Figure 13b). The interviewer then asked, “So why can you do it in two different ways here [pointing to Grasplify], but you don’t do it in two different ways here [pointing to Zaplify which is showing 4 × 3 on a different iPad]?” Wayne said, “Is it because you tried to make them harder?” This points to an untranslatable, that you can switch in Grasplify, but not in Zaplify.
In Grasplify, the students switched hands quite quickly (we showed an example earlier of Leo switching from 8 × 5 to 5 × 8). However, we never saw them switch factors in Zaplify. We hypothesise that it is because the visual display changes so much in Grasplify, so that 4 × 3 is seen as being different from 3 × 4 (though also being the same). Also, the two sides of Grasplify host different kinds of numbers: one side is the unit, the other side is the number of copies of the unit. For both of these reasons, switching sides seems to make a difference for students. In Zaplify, however, the difference is not recognised. Not only would the grids look very similar when the horizontal is switched with the vertical, but also the two sides (left and bottom) create the same kind of objects (the two factors).
Of course, it is possible to switch hands in Zaplify, but no student ever did. We interpret this as an awareness they have of the symmetry of Zaplify, that is, that placing 7 fingers along the bottom and 5 along the side will produce “the same” as placing 5 along the bottom and 7 along the side. Moreover, we suggest that by not switching, they are showing a sense of hospitality in Zaplify, by respecting its particular way of showing multiplication and not forcing into it the ways of working in Grasplify.
Related to this issue of switching, the only time we heard the students comment on the difference in Zaplify was when Leo was asked which world was better for showing that 4 × 5 is the same as 5 × 4. He first chose Grasplify, but then switched to Zaplify. He created 4 × 5 and described “there are four dots, five times”. He hesitated for five seconds and then turned the iPad 90 degrees, saying “When you look at the portrait, you can see it, (he then turns the iPad 90 degrees), when you look at landscape you can also see it”. We note that in this explanation there is no switching of hands, only a change of perspective.
We saw a similar untranslatable when we asked Ian and Fabian to vary the button problem, so that there would only be four heaps (instead of five). In Grasplify, Ian released one pip-finger, while Fabian started to drag one pod into the trash bin. When Ian asked him why he was doing that, Fabian replied, “because four buttons” and Ian responded, “four buttons in each pile”, to which Fabian agreed. Subsequently, when the interviewer asked about decreasing the number of buttons in each heap again, they were quick to lift a pip-finger. In comparison, when asked to increase the number of buttons in each heap in Zaplify (from five to six), they spent more time discussing where they should tap, the left side or the bottom. They had made five horizontal rows and eight vertical ones. Ian tapped once at the bottom (creating nine vertical lines) but soon realised that it was incorrect. Fabian tried to help by tapping on the top of the screen to add one more horizontal line and said, “that’s six”, but Ian said, “but that’s nine”. Eventually, Ian cleared the screen and restarted. He made six horizontal lines, then locked the screen, and made eight vertical lines. When asked, “what if there were seven buttons?”, Ian made one more vertical line but realised that it was incorrect and restarted. We see this as a similar untranslatable because it seems related to the fact that the two quantities play more distinct roles in Grasplify, which seems to make it easier to vary the problem, while the two quantities in Zaplify are harder to distinguish. In other words, the distinctness of Grasplify cannot be expressed in Zaplify.