During these next few weeks, I continued with multiplication for my 10th grade students, but crossed into double-digit numbers and even some triple digit multiplication.
It was interesting to see how the students reacted the first time I put up a double-digit multiplication problem. You could literally hear sighs in the classroom! However, as I continued to do them, I got less and less push back on the difficulty. What I found is that the students who offered their answers were able to transfer strategies from the earlier number talks to these more difficult multiplication problems.
One struggle that I still have is that I believe a few students are really struggling with their basic math facts and this is seriously inhibiting their ability to participate in the number talks. I can think of at least 5 students who do not have their basic multiplication facts memorized (like 6x8). I'm not quite sure how to have them still participate fully during this time and at the same time continue to push the other students in the class to think more deeply about multiplication.
Another thing that I ran into during these number talks was that students were not distributing when they were breaking up numbers. For example, the number talk 15 x 13. There were some students who wanted to break up the 15 into (10 +5) and the 13 into (10+3) and then they wanted to multiply. However, they were not distributing when they multiplied so they were only performing these operations: 10 x 10 + 5 x 3.
This brought up a good discussion in each class and I was able to introduce the area model for them to see why we had to distribute.
Below are some of the number talks with two digit multiplication.
I am planning to stay on multiplication throughout the rest of the semester, however am transitioning to using money to have my students think about bigger numbers. For example, I will do problems like $1.99 x 6.
I am hoping that they will use strategies they have already seen to think about these types of multiplication problems and I am hoping they will also come up with new strategies because of the different context of money.