How to use factors and grouping to multiply by tens?

This model demonstrates the ease with which a student can find the product. At first, have your students count the tens blocks, and then have them count the ones blocks to enhance the concept of addition. They will count 6 tens and 12 ones. Then demonstrate how to regroup the 12 ones to make one ten block and 2 ones. A final count will yield 7 tens, 2 ones, or 72.

Although some exercises may not involve regrouping, have your students check them all to decide whether regrouping is needed. Some students may decide to add 3 groups of 24. This method involves regrouping the ones. Further regrouping resources are available in Grade 3, Regrouping to Multiply and Divide.

Once students become familiar with using the models for multiplying, have them record the multiplication alongside the model to show each individual step, including the regrouping, if needed.

40%=2/550=1/230=3/1056=14/25