Explain that you can decompose 100 into tens. If you know the decompositions of 10 well, it will be easy to decompose 100. 4 and 6 make 10, and 40 and 60 make 100. Show how they make 10 and 100 respectively. In each situation a zero is added to the end to make 100 total. Show that you can switch the numbers in a number bond. So 10 and 90 make 100 but 90 and 10 also make 100. Check that students can decompose 100 dollars by dragging tens to the children and ask students to decompose 100 in three ways. Explain that we will be composing in 10s. Then compose 100 from 25 and 75. With the 10 and 5 dollar bills, show students that they first count 5 more and then 70. Explain that 75 and 25 always make 100 and 25 and 75 also make 100. Practice with the students.

Check that students can decompose and compose 100 from tens and 25 and 75 by asking the following questions:

- How can you easily decompose 100 into tens?

- Can you name a few decompositions of 100 in tens?

- Which number goes with 25 to make 100?