When composing to 1, the students should always start by composing to the next tenth (first place after the decimal point) and then to 1. In this case you go from 0.68 to 0.70, an increase of 0.02. Then you compose 1, which means 0.30 more is counted. The total of 0.30 + 0.02 = 0.32. Practice composing to 1.00. In dragging the coins and bills, you also show the decomposition of the whole 1.

When composing to 10, the students should always compose to the next tenth (first place after the decimal point), then to the next whole number, and then to 10. In this case you go from 3.65 to 3.70, an increase of 0.05. Then you go to 4.00, an increase of 0.30. You then compose 10.00, an increase of 6.00. The total of 0.05 + 0.30 + 6.00= 6.35. You practice this by composing 10.00. By dragging the coins and bills, you also show the decompositions of the whole 10.00.

To compose to 100 students first compose to the next whole number, then to the next ten and then to 100. In this case you go from 85.90 to 86.00, an increase of 0.10. Then you go to 90.00, an increase of 4.00. You finally compose 100, an increase of 10.00. The total of 0.10 + 4.00 + 10.00 = 14.10. You practice this by composing $100.00. By dragging coins and bills, you also show the decompositions of the whole 100.00.

To check that students understand composing decimal numbers to 1, 10, and 100, you can ask the following questions:

- Compose 1: 0.2 and...?

- Compose 1: 0.22 and...?

- Compose 10: 5.8 and...?

- Compose 10: 7.99 and...?

- Compose 100: 96.5 and...?

- Compose 100: 92.25 and...?