1.OA.6 / 2.OA.2 - Mental Math Strategies: Break Down to 10

In this video, Mr. Almeida explains how to use mental strategies to subtract within 20 using the "break down to 10" strategy. This is one of the strategies suggested in the Common Core State Standards for Mathematics, 1.OA.6 and 2.OA.2.

With practice, this strategy can help students gain fluency when subtracting within 20. Eventually students will memorize these facts, which is expected by the end of grade 2.