This week, we began Number Talks during our math instruction time. Number talks are classroom conversations about simple math problems that are solved mentally. Mental math helps students to gain a better ‘number sense’ and build upon number relationships instead of relying on memorized procedures. By using mental math, students become familiar with how numbers interact. Students use this as an opportunity to recognize misconceptions and investigate thinking and learn from mistakes.
Here’s how it works: the class gathers in the front of the classroom and is presented a problem such as 19 + 21. The class is asked to think about how to solve the problem. When they have the answer, they put a thumb up on their chest. If they are finished before the talk begins, they are asked to think of another way to solve the problem.
When the students all have at least one answer, I take solutions from students and then write them on the board. I have the student talk the class through the mental process they used for solving the problem. Students defend or justify their answers to the group. For example, one way a student may solve this problem is by taking the 1 from 21 and making the number 20, then adding that 1 to 19 and making that 20. Mentally adding 20 + 20 is easier than mentally adding 19 + 21. Students defend or justify their answers to the group. Another way to solve this problem would be to add the 10 from 19 and the 20 from 21 to equal 30, then add the 1 and the 9 to equal 10, then add the 30 and 10 to equal 40. A video example of a number talks lesson can be found at: https://www.youtube.com/watch?v=SPEfxPgZJy4
We talk about ‘friendly numbers’. These are numbers that are easy to add in your head, like base ten numbers. We also talk about ‘decomposing’ numbers, which is like the example above of taking the 1 away from 21 and adding it elsewhere.
As the problems become more complex, mistakes will be made, and that is when a lot of learning happens. Students often recognize mistakes as the problem is being solved aloud. Number talks help your child to make sense of mathematics, develop efficient computation strategies, and learn from mistakes that are made.
You can practice your own small number talks in the car, while you are at home, or anytime. Your student will become better at math if you do!