At the start of our math lesson, second graders have been talking about numbers. During these ‘Number Talks’, students talk about the method they used to solve a problem. Students get to share their strategies with one another. By doing so students are learning to explain and express their thinking as they solve problems using mental math. There have been a lot of 'ah ha' moments when students express a variety of ways to derive at the same answer.
A Number Talk is a powerful tool for helping students develop computational fluency because the expectation is that they will use number relationships and the structures of numbers to add and subtract. The heart of Number Talks is classroom conversations focused on making sense of math. Children are developing computational fluency while thinking and reasoning like mathematicians.
For example, one of our talks asked the following question: How does 9 + 4 help you solve 29 +14? Students could see the relationship because of place value. One student offered the following as his way of applying his mathematical knowledge to solve this problem:
9 + 4 = 10 +3, equals 13
Another student solved it this way:
20 + 10 = 30
I know that 8 + 5 = 13
therefore, 30 + 13 = 43
We end our Number Talk sessions with a ‘cheer’ to celebrate the fact that students can use different approaches to solve problems, and end with the same result. Our cheer this week is “Na na na na! Na na na na! Hey, Hey, Hey! GOOD JOB!”