Wednesday, March 21, 2012

Drilling Exponents

After our successful intro to exponents in Grade 8, I feel that the students can mostly articulate how to simplify exponents and why, and that they were ready for some more focused drill / practice. We are about halfway through the exponents mini-unit -- haven't yet introduced negative or fractional exponents yet, but they should be pretty OK with everything else by now.

Since I have been looking for creative ways to stay within my printing quota, I thought of a move-around activity for my students. So, I put up a bunch of different questions around the room (a total of 22 problems) on index cards, and asked them to move around to try simplifying each one. The answer is on the back (written upside-down so that when they flip it over along the top edge, it becomes right-side up), so they can quickly check their own answers to know if they are on track. Their task was to do as many as they could, to mark the ones that they had gotten incorrect*, and to ask me for help if they really cannot figure out, even after looking at an answer, how that answer was obtained.

*I had asked them to mark the ones that they initially got incorrect, so that in case they come to me asking for more practice problems later, I would know which type of questions to make for them to address their individual issues.

It was great! Kids really got to move at their own paces, and most of them finished all 22 questions and started a new assignment. Also, because they were already moving around the room, kids who don't typically collaborate during class started working together in random corners of the room. I think the on-the-spot answer-checking was also good for the weaker students, because they can address their own gaps (and also move at their own pace) without feeling insecure about it, and if they did get something correct on the first try, it was a nice boost for their confidence.

Exponents, unfortunately, is such a hellishly boring topic. The move-around activity and also speed games** help to make it a bit more exciting, I guess. (Because we haven't played too many games this year in Grade 8, the idea of group games is still fantastically fun for them...)

**I think I wrote about my typical games format a while ago. Very simple: Two teams, each team sends up 2 people at a time. The teammates can collaborate at the board but when they raise their hands with an answer, only one will be chosen "at random" to explain the answer. Most of the time the teams figure out to pair a strong student with a weak student, and they figure out also that the weaker student will probably be asked to explain, so at the board the stronger student is trying to explain the concept to the weaker teammate -- perfect peer learning opportunity! It also keeps rotations faster so there is less crowd idleness. Problems that are unanswered at the board go to the crowd for 0.5 point, so that is an additional incentive for the audience to stay looped in and to try the problems at their desks.


  1. i have a crapload of board space in my room with 5 mini-whiteboards and two huge wall whiteboards... and we are just starting to do anti-derivatives. so this is peeeeerfect. thank you Mimi!

  2. Great! I think this is perfect for skills-heavy topics.

  3. How do you keep the kids from cheating and just writing down the answers?

  4. Kids in my class don't get any credit for classwork, so there is no incentive to cheat on in-class assignments. (I also give them full credit just for trying the homework, to take away incentive for cheating on homework.) I often circulate answer keys as or after they are working on something, to help them make sure that they're on the right track. I'd say that if you are concerned about them "cheating", just clarify the intention of the activity at the start and give them a structured worksheet for showing work in getting them to the posted answer. Say that their work should be so clear that they are ready to explain all processes the next day during whole-class discussion.