Paging Doctor Math: Jenga Task

Wednesday, February 25, 2015

Jenga Task

I always like to make sure my students get as many quality tasks as possible, so when I came across the idea of this task, which is arguably more at a 6th grade level, I still wanted my 7th grade students to have the experience since we did not do this last year in 6th grade. You cannot have enough problem solving experiences in your classroom! I also gave this task to my current 6th grade students.

Here is the original task courtesy of @daneehlert.

Here is my modified version of the task as the students viewed it...

http://bit.ly/19eFrJg

While not a huge difference in question three, I decided to use the fraction 6 1/2 with the 6th grade students and 6 5/8 with my 7th graders. 6 5/8 is easier for my 7th grade because they are more fluid with fractions and decimals at this point. My 6th graders could have used 6 5/8, but I think the length of time the computation would have taken is not as important the problem-solving outcomes I am looking for.

We had a problem starting this task because all I gave them was the information on the modified task link. The students weren't sure how to read the label for the board that was $2.72. We stopped and had a discussion of what 2 by 4 by 96 meant. Once the students understood that the boards purchased at the store were 96 inches in length, they were able to begin.

I am all for calculator use as long as students explain their understanding, but I think the calculator actually became a hinderance for this problem...especially on question 3. When the students got 14.4 when they divided 96 by 6 5/8 or 14.7 when they divided 96 by 6 1/2, many thought this was the leftover inches but it was really how much of the extra board was left. This problem was personified from question 1 when students did 96/10 and got 9.6. Not only is .6 end up being 6/10 of a board which is 6 inches, but it is also the leftover amount of inches. This is one of those math occurrences where it just happens to work out that way. Students who draw a picture were much more successful, at least in the short term.

Question 2 was either very brief or fairly time consuming depending on how the students thought about it. Many students figured out that if you are using all 96 inches, you have 480 inches available which exactly matches the length of the boards in the life-size Jenga tower. Others took a more systematic approach, buying a board and saving the leftover until they could create another piece of the tower.

Finally, the terminology I used was fairly confusing from the standpoint of the 96 inch board and the 10 inch board. I needed to have a different word than "board" for both of these items to alleviate confusion.

Here are the standards I attached to this task, along with student work and the set-up page I created for the task. Overall, this was an enjoyable task and the students liked the concept of taking something like the Jenga game and the plausibility of actually making it life size.

7.NS.A.3

6.NS.A.1

6.NS.B.2