1.   Use models to write an expression and a number sentence. Then solve.

A secretary made 12 photocopies. Then she made 4 more. How many photocopies did she make in all?

    A. 12 − 4; 12 − 4 = 8 B. 12 + 4; 12 + 4 = 18
    C. 4 + 8; 4 + 8 = 12 D. 12 + 4; 12 + 4 = 16
    Hint

  2.   The + symbol makes which statement true?
    A. 18 ___ 9 = 9 B. 8 ___ 4 = 12
    C. 15 = 20 ___ 5 D. 1 + 7 = 16 ___ 8
    Hint

  3.   The − symbol makes which statement true?
    A. 16 ___ 6 = 7 − 3 B. 50 ___ 12 = 64 − 2
    C. 27 ___ 3 = 24 D. 6 + 11 = 10 ___ 7
    Hint

  4.   The − symbol makes which statement true?
    A. 3 + 6 = 4 ___ 5 B. 8 = 14 ___ 6
    C. 4 ___ 8 = 21 − 9 D. 12 ___ 5 = 17
    Hint

  5.   Use counters to show whether + or − makes the number sentence 8 ___ 6 = 2 true. Explain.
    A. +; 2 counters + 6 counters = 8 counters altogether. B. +; 6 counters + 2 counters = 8 counters altogether.
    C. −; 6 counters − 8 counters = 2 counters left. D. −; 8 counters − 6 counters = 2 counters left.
    Hint