Multiplying Fluently by Subtracting from Groups of 10

This lesson teaches how to multiply fluently by subtracting from groups of 10. It begins with a review of 10s quick facts and the commutative property of multiplication. The lesson then demonstrates how to multiply numbers like 4 * 9, 6 * 9, and 9 * 8 using a strategy that involves subtracting from groups of 10. This approach simplifies multiplication by leveraging known facts and reducing the need for direct calculation.

Describe how to visualize the multiplication of 10s quick facts.

How does the strategy of subtracting 1 from each group help in multiplication?

What is the significance of subtracting from groups of 10 in multiplication?