In the Powerful Problem Solving book that’s coming out this month (!) we included the famous “Make a Peanut Butter and Jelly Sandwich” activity, in which students write instructions for making a sandwich and then their teacher or partner acts the instructions out very literally — e.g. “put the peanut butter on the bread” is interpreted as “place the (unopened) jar of peanut butter on top of the pile of bread.” Or “spread the peanut butter on the bread” doesn’t imply “with a knife” so you’re scooping out globs and globs of peanut butter and smearing it all over all sides of the bread with your fingers.
I got to visit a classroom where the activity was being implemented. The activity is in a chapter on good math communication and focuses on the important of revision. Watching the activity in action, I was struck by the subtle differences between focusing on precision and focusing on revision.
If you focus on precision, this can become a kind of “gotcha” activity. An activity in which the teacher sets up the kids by saying, “hey, this is really simple, everyone knows how to make a PB&J, so of course you can explain it…” knowing that they won’t be able to explain it to the alien the teacher is going to pretend to be, without warning them. The message the kids might take away is “writing in math class means painstakingly explaining your work to someone pretending to be an idiot” which is clearly not fun. There’s a reason the word “pain” is the first syllable in “painstaking!”
Because in fact, giving instructions that teach someone how to do something is NOT easy. The tricky part of giving instructions is figuring out what the other person does and doesn’t know, and tailoring (aka revising) your instruction to meet their needs.
When I watched the “Make a Peanut Butter and Jelly Sandwich” activity, the teacher had a GREAT launch — she showed a picture of an alien and explained that on Bob the Alien’s planet, they’d picked up radio transmissions of “Peanut Butter Jelly Time.” Bob wants to know what this amazing experience of making a peanut butter and jelly sandwich might be, since the aliens so enjoyed hearing the song!
So right away the students were in a mindset of needing to figure out how Bob the Alien thought. After the teacher acted out some instructions as Bob, the kids started to say, “Wait, Bob has no common sense!” and “Bob is taking these directions SO literally!” and then “Wait, can I change my instructions?” or “I need to revise this part.”
The activity was structured to have lots of revision moments built in — once after seeing “Bob” in action on some sample directions and then again after having a peer pretend to be Bob. The students revised other people’s instructions, not their own, to help make the revision not personal, and more about thinking about what they’ve learned about Bob.
The teacher’s language can help reinforce that we’re revising based on new data, not just recognizing that we should have done better the first time. The teacher can ask, “What are some different ways you think Bob might interpret that? How would you change your instructions if Bob did this instead of that?” The teacher can also ask, “What did you think about Bob before he read the first directions? How did your thinking change after you saw how he interpreted them?”
Writing instructions on how to make a Peanut Butter and Jelly Sandwich for an alien can be a great experience that helps students understand what revision is, why we revise, why feedback from others is an important part of revision, and why explanations might need to take different perspectives into account. The key is to make sure that the expectation is that we will get new information about how the alien thinks and revise based on that. This is not a “haha, you thought you knew how to write instructions!” It’s a “wow, that alien sure does interpret things weirdly, I guess I’ll have to try again now that I know that!”
Finally, it’s nice to have the students be the ones to articulate what they learned from the experience. After the activity, it’s neat to wonder, “What does this have to do with math?” or “What math experiences does this remind you of?” One thing I thought I might do is make an audience-o-meter with “Bob” at one end and “Myself” at the other and try to think about different audiences we might write mathematical explanations for, and the levels of detail, amounts of revising, etc. that we might need to include depending on where we are on the audience-0-meter.
PS — with the rising prevalence of peanut allergies you might want to make cream cheese and jelly sandwiches, or use American cheese slices, or do instructions for brushing your teeth…
PPS — Another cool part of the activity is when the students get to be Bob. They’re playing with the mathematical skill of coming up with a counter-example, of finding other ways to interpret a mathematical definition or instruction… which is so important! It’s sort of like they’re practicing the skills in this amazing play-let based on key moments in modern Geometry.


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Hey Max – I love this. I am wondering what grade this was done with, and at what point in the school year. Thanks – WM
Hi Wendy, this was 9th graders on the 4th day of school at a large, diverse, high percentage of free and reduced lunch district. Only a very little bit of peanut butter ended up smeared on group members inappropriately (I blame flirting/showing off for girls).
[...] most is to Attend to Precision (as evidenced in things like the Peanut Butter & Jelly activity, depending on how you do it.) Students should practice saying what they mean in a way that is understandable to everyone [...]
This activity reminded me of the Kindergarten activity of putting directions in order. Each child had to pick a simple task of making something or doing something, i.e. making a sandwich or playing a video game. I see a teachable moment to start at an early age to notice details by giving literal examples of their directions. The activity could be given a couple more times throughout the year to document improvement and know where your students are in their thinking process.
I also believe this Peanut Butter Jelly Time activity could help those students with Asperger’s Syndrome and others who think very literally. The inclusion of the alien is an important piece. The inclusion of the alien helps the children know that they have to think of everything done exactly because the alien doesn’t know about anything on Earth.
Thanks for sharing a great idea for any grade level.