L14 · Four operations with negative numbers

1. 1.

   Evaluate 5 + (−4) × (−1).

   Answer. 9

   Multiply first: −4 × −1 = 4. Then 5 + 4 = 9.

2. 2.

   Evaluate 7 + (5) × (4).

   Answer. 27

   Multiply first: 5 × 4 = 20. Then 7 + 20 = 27.

3. 3.

   Evaluate 5 + (6) × (5).

   Answer. 35

   Multiply first: 6 × 5 = 30. Then 5 + 30 = 35.

4. 4.

   Evaluate 8 + (−2) × (3).

   Answer. 2

   Multiply first: −2 × 3 = −6. Then 8 + −6 = 2.

5. 5.

   Evaluate −4 + (4) × (4). Then Nora needs 2 of that amount. What is the total they need?

   Answer. 24

   Multiply first: 4 × 4 = 16. Then −4 + 16 = 12. Then multiply by 2: 24.

6. 6.

   Evaluate 7 + (5) × (5). Then Elena needs 5 of that amount. What is the total they need?

   Answer. 160

   Multiply first: 5 × 5 = 25. Then 7 + 25 = 32. Then multiply by 5: 160.

7. 7.

   Evaluate −3 + (−3) × (−3). Then Mei needs 2 of that amount. What is the total they need?

   Answer. 12

   Multiply first: −3 × −3 = 9. Then −3 + 9 = 6. Then multiply by 2: 12.

8. 8.

   Evaluate −5 + (−2) × (−3). Then Sam needs 5 of that amount. What is the total they need?

   Answer. 5

   Multiply first: −2 × −3 = 6. Then −5 + 6 = 1. Then multiply by 5: 5.

9. 9.

   Evaluate 2 + (−2) × (−1). Then Theo needs 4 of that amount. What is the total they need?

   Answer. 16

   Multiply first: −2 × −1 = 2. Then 2 + 2 = 4. Then multiply by 4: 16.

10. 10.

    Evaluate −5 + (2) × (−5). Then Mei needs 2 of that amount. What is the total they need?

    Answer. −30

    Multiply first: 2 × −5 = −10. Then −5 + −10 = −15. Then multiply by 2: −30.

11. 11.

    Think

    Nora tried this problem:
    Evaluate 2 + (3) × (2).
    Nora wrote -8. That is not correct. What is the right answer?

    Answer. 8

    Nora’s answer -8 is off. Multiply first: 3 × 2 = 6. Then 2 + 6 = 8.

12. 12.

    Think

    Priya tried this problem:
    Evaluate 3 + (−5) × (−3).
    Priya wrote 19. That is not correct. What is the right answer?

    Answer. 18

    Priya’s answer 19 is off. Multiply first: −5 × −3 = 15. Then 3 + 15 = 18.

Original extra practice. Keys are computed from the items, not guessed.