Multiplying and Dividing Integers Test Answer Key with Scoring – Grade 7

Question 1 Multiplying Integers (2 points)

(a) 9 × 8 = 72, signs differ: −72.

(b) 6 × 12 = 72, signs match: 72.

−72 and 72

Scoring: 1 point per part.

Question 2 Dividing Integers (2 points)

(a) 84 ÷ 7 = 12, signs differ: −12.

(b) 90 ÷ 15 = 6, signs match: 6.

−12 and 6

Scoring: 1 point per part.

Question 3 Decimals and Fractions (3 points)

(a) 1.6 × 0.45 = 0.72, signs differ: −0.72.

(b) 3045 = 23, signs match: 23.

(c) 78 × (−27) = −1456 = −14.

−0.72; 23; −14

Scoring: 1 point per part.

Question 4 Number Line Jumps (3 points)

(a) 4 × (−5) = −20.

(b) −20 ÷ 4 = −5.

(c) The signs match, so the product is positive: (−4)(−5) = 20.

4 × (−5) = −20; −20 ÷ 4 = −5; 20

Scoring: 1 point per part.

Question 5 Pattern of Products (3 points)

(a) 0, 6 and 12.

(b) Each result is 6 more than the one above it.

(c) The product of two negative numbers is positive.

0, 6, 12; results rise by 6; negative times negative is positive

Scoring: 1 point per part.

Question 6 Retreating Glacier (3 points)

(a) 8 × (−2.5) = −20 meters.

(b) (−2.5)(−6) = 15, so the edge was 15 meters farther out.

(c) −35 ÷ 14 = −2.5 meters per month.

−20 m; +15 m; −2.5 m per month

Scoring: 1 point per part.

Question 7 Zero and Division (2 points)

(a) 0 ÷ (−13) = 0.

(b) If 9 ÷ 0 = q, then q × 0 = 9, which is impossible because any number times 0 is 0.

0; undefined

Scoring: 1 point per part.

Question 8 Distributive Property (2 points)

Way 1: 5 − 9 = −4, and −6 × (−4) = 24.

Way 2: −6 × 5 − (−6) × 9 = −30 + 54 = 24.

24

Scoring: 1 point for each method.