Write the following subtraction problems on the
board. Ask students to solve each of the facts.
9 − 8 9 − 5 10 − 6 9 − 1
- Which problem did you solve using a counting
strategy? (Possible response: 9 − 1 or 9 − 8)
- Did you use counting up or counting back?
- Did you like that strategy? Why?
- Did you use reasoning strategy to solve any of the problems?
- Which problem? (Possible response: 10 − 5 = 5 so
9 − 5 = 4.)
- Describe the strategy. What other facts did you use?
- Did you use an addition fact to help you solve a subtraction problem?
- Which fact and how did you use it? (Possible response: 6 + 4 = 10 so 10 − 6 = 4.)
- Which facts are helpful? (the facts that make ten and the doubles)
Use Check-In: Questions G–H on the Counting Strategies
page in the Student Activity Book to assess students' abilities
to use the counting up and counting back strategies with the
subtraction facts [E5].
Use Check-In: Questions F–G on the Use Other Facts: Small
Numbers pages or Check-In: Questions D–E on the Use the
Other Facts: Larger Numbers pages in the Student Activity
Book to assess students' abilities to reason from other facts
to solve subtraction problems [E5] and apply the properties
of addition to solve subtraction problems [E6].
