IM 6.5.9 Lesson: Using the Partial Quotients Method

Elena used base-ten diagrams to find . She started by representing 372. She made 3 groups, each with 1 hundred. Then, she put the tens and ones in each of the 3 groups. Here is her diagram for . Discuss with a partner: Elena’s diagram for 372 has 7 tens. The one for has only 6 tens. Why?

Discuss with a partner: Where did the extra ones (small squares) come from?

Andre calculated using a method that was different from Elena’s. Andre subtracted 600 from 657. What does the 600 represent?

Andre wrote 10 above the 200, and then subtracted 30 from 57. How is the 30 related to the 10?

What do the numbers 200, 10, and 9 represent?

What is the meaning of the 0 at the bottom of Andre’s work?

How might Andre calculate ? Explain your reasoning.