1.   Find the number that completes the number sentence. Then identify the property or rule.

12 − ∅ = 12

    A. 0; Commutative Property of Addition
    B. 0; Subtraction Rule
    C. 0; Associative Property of Addition
    D. 43; Identity Property of Addition
    Hint

  2.   Find the number that completes the number sentence. Then identify the property or rule.

24 + ∅ = 18 + 24

    A. 0; Identity Property of Addition
    B. 6; Subtraction Rule
    C. 18; Associative Property of Addition
    D. 18; Commutative Property of Addition
    Hint

  3.   Find the number that completes the number sentence. Then identify the property or rule.

(21 + 13) + 56 = 21 + (∅ + 56)

    A. 13; Commutative Property of Addition
    B. 21; Identity Property of Addition
    C. 35; Subtraction Rule
    D. 13; Associative Property of Addition
    Hint

  4.   Find the number that completes the number sentence. Then identify the property or rule.

43 + ∅ = 43

    A. 0; Commutative Property of Addition
    B. 0; Associative Property of Addition
    C. 0; Identity Property of Addition
    D. 12; Subtraction Rule
    Hint

  5.   Add mentally.

18 + 41 + 12

    A. 82 B. 81
    C. 71 D. 61
    Hint