N1C4TNp10

Answer to Problem 10: Answers may vary. Examples: 80 – 4; 70 + 6; 75 + 1; 100 – 24

TEACHER NOTES:

By fourth grade, students should be able to think of 36 as 30 + 6 or 20 + 16 or 9 ´ 4. This flexibility in number sense builds on strategies that students should be developing in the primary grades.

DEFINITION:

decomposing and composing numbers—flexibly using or knowing numbers through creating and breaking numbers apart to form equivalent representations. For example, 36 can be thought of as 32 + 4, 20 + 16, 40 – 4, 12 ´ 3, 72/2 etc.[1]