Bag of Tricks #1 – Index Cards

In “Bag o’ Tricks” posts, I’ll give activities that require almost zero prep, but inject a shot of fun, practice, activity, assessment, remediation, or whatever in a small amount of class time.

This post’s focus is index cards.  My students like them – I think they are just nicer objects than sheets of paper.  These are perhaps my favorite no-prep activities.

Memory (20 minutes)

  1. Each student gets two index cards.
  2. On one index card, each student writes an expression of a given type (e.g. an anonymous differentiable function like “2x+sin(x)”).  Every student must use a pencil.
  3. On the other index card, each student writes a corresponding expression after a given operation (e.g. differentiation – “2 + cos(x)”).  After this step each student has two cards that are connected by the given operation, but not by name or any other property.
  4. In pairs, students swap cards and check each other’s work.
  5. Each student gets another two index cards and repeats the process.  Each student now has a total of four cards, two pairs of linked cards.
  6. Students form groups of four, shuffle their combined sixteen cards together, and lay them out upside down.  The cards are (hopefully) indistinguishable.
  7. The students play memory (in teams of two, or not).  A team flips over one card, and then another.  If they match through the operation, they keep the pair, get a point, and go again.  If the cards don’t match, the next team is up.

This activity is great, after you figure out how to make sure students write problems of the appropriate difficulty.  They need to be pretty easy.  Memory is hard when its just pictures of barnyard animals, you know?  I use it to have students practice derivatives over and over again.  Every time they see, for example, “2x,” they have to think “what is the derivative of 2x, and what might have 2x as a derivative?”  You need a problem that’s easy, but takes lots of practice.  Distributing polynomials, finding logarithms, solving linear equations, etc.  The first time I used this activity I put, like, physics word problems on one card and answers on another.  Let’s just leave it at “don’t do that” and move on, please ;).

Benefits of memory:

  1. A bunch of practice
  2. It’s reasonably fun
  3. Kids write their own problems and solve them
  4. Each student gets the advantage of knowing 2 of the 8 answers right away.  This almost guarantees some success for every student – everyone can feel engaged, even if their skill level is lower than the others’.

Write and Swap (5-7 minutes)

  1. Each student gets an index card and creates an example problem.
  2. Students swap cards at their table (I have tables of two) and confirm that the problems are in the proper form, etc.  Any questions about problem creation are resolved.
  3. The teacher moves quickly and energetically around the room, picking cards swiftly out of kids’ hands and giving them replacement cards from other kids.  This works elegantly – the teacher can move in any pattern, so as soon as problems are written they can be swapped out, but students who need more time may take it as the teacher is passing out cards.
    After this step each student has a new card in front of them, and they don’t know exactly where it came from.
  4. Each student solves the problem on his or her card.
  5. Students swap cards at their table and confirm solutions.  Any questions about problem solution are resolved.

Benefits of write and swap:

  1. Each student gets practice writing a problem, which may involve critical thinking about what is important to include.
  2. Each student thinks about four different problems in a row, but a physical interaction between each problem keeps attentions focused.
  3. Student responsibility is diffused.  Limited responsibility can help students feel safe, which can be important (though students should be fully responsible for at least some work every day).
  4. A peppy teacher can infuse the activity with energy on a slow day by zipping around the classroom in the big card swap.  Carry around a funny container instead of just holding the cards in your hand if you want.

Write and Swap is great for those times when you just want students to practice something kind of boring a few times.  It’s not great for longer problems because the phases get unsynchronized.

Most confusing part (5-7 minutes)

I got this from Science Formative Assessments, by Page Keeley.

  1. Each student gets one index card near the end of the period.
  2. Each student writes, anonymously, the thing about the class that was most confusing, least fun, whatever.
  3. The cards all go in a box and are redistributed, one card per kid.  Page Keeley recommends having the kids literally throw the cards around, but I admit to not being brave enough to try this yet.  It might make this activity really fun… or just add two minutes to its execution.
  4. Kids read their new cards aloud to the class.

The first time I tried this, I wasn’t that impressed with the results, but like any new technique I’ve gotten better at making it succinct and useful.  This activity is mostly to get a quick sense of how your lesson went, if you didn’t have any better way to do it built in.


  1. If a theme emerges, you know, that’s a great piece of information for the teacher.  Write that down on your lesson plan!
  2. You get to hear from every kid in a very low-pressure way.
  3. I imagine that kids who are embarrassed by a lack of understanding are heartened when they (inevitably(!)) hear that someone else had the same problem.

5 thoughts on “Bag of Tricks #1 – Index Cards”

  1. I found your site by reading Kate at f(t). All I can say is Wow! I love, love, love your index card ideas. I teach 8th grade math and algebra, but I’m going to steal that idea and use it tomorrow. Looking forward to your next post!

  2. Thanks for this…After reading it I added one variation to my bag of tricks. I have them do a warm-up problem (one that I know some can do and some can’t) on an index card. I collect and redistribute, we review, I ask who’s holding a card that has it right and make a list of those student’s names on the board. Then we break up into groups of 3 or pairs. Each group/pair must have someone who did it right and we get 2-3 more similar problems. So far it has worked like a charm.

  3. Thanks for the tip, Chuck. Is there ever any embarrassment or tense feelings when asking who has a correct card? Do you, as the teacher, say what the correct answer is, or rely on the kids to know a correct card when they see one?

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