Grade 7 Integers: Multiply/Divide Rationals

Multiply and divide rational numbers

What You'll Learn

Apply sign rules to decimal products
Divide positive and negative decimals

📖Sign rules

Multiply or divide the numbers without their signs, then decide the sign: same signs give a positive answer, different signs give a negative answer. (−1.5) × 4 = −6 and (−7.5) ÷ (−2.5) = 3.

💡Decimal divisors

To divide by a decimal, multiply both numbers by 10 or 100 so the divisor is a whole number: 4.8 ÷ (−0.6) is the same as 48 ÷ (−6) = −8.

Worked examples

Real problems from the practice worksheets, solved one step at a time.

Example 1
(−15) ÷ 1.5 = ?
1. Divide the numbers without their signs: 15 ÷ 1.5 = 10.
2. The signs are different, so the answer is negative.
3. (−15) ÷ 1.5 = −10
Answer: −10
Example 2
(−5.8) × 4 = ?
1. Multiply the numbers without their signs: 5.8 × 4 = 23.2.
2. The signs are different, so the answer is negative.
3. (−5.8) × 4 = −23.2
Answer: −23.2
Example 3
4.4 × (−0.5) = ?
1. Multiply the numbers without their signs: 4.4 × 0.5 = 2.2.
2. The signs are different, so the answer is negative.
3. 4.4 × (−0.5) = −2.2
Answer: −2.2