7th grade · Math · Unit 13 of 17
Multiply & Divide Signed Numbers
Sign rules
What your child practices
Multiplying and dividing positive and negative numbers (including fractions), using the sign rules, and real-world changes such as falling temperatures.
Alaska content standards learning standard: 7.NS.2 · multiplying and dividing rational numbers, including negative numbers
How we explain it
Children can open this short lesson before they practice.
- Multiply or divide the numbers as usual.
- Same signs give a positive answer.
- Different signs give a negative answer.
Example: What is −6 × 4? 6 × 4 = 24. Different signs: negative. Answer: −24
Multiply & Divide Signed Numbers in Alaska
In the Alaska content standards, this is unit 13 of 17 in 7th grade Math, after Mean, Median & Mode and before Proportional Relationships.
Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.
Source: Alaska Department of Education and Early Development
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
What is 1/5 × (−25)?
- -4
- -5
- -8
- 5
-5
Hint: 25 ÷ 5 = 5. One factor is negative, so the answer is negative.
Question 2
What is 30 ÷ (−6)?
30 ÷ (−6) = ?
answer box
-5
Hint: Divide the sizes, then use the sign rule: same signs positive, different signs negative.
Question 3
Without multiplying: is 3 × (−1) × (−1) positive or negative?
- Positive
- Negative
Positive
Hint: Count the negative factors. An even number of them gives a positive product; an odd number gives a negative one.
Question 4
The temperature falls 3 degrees every hour for 2 hours. What is the total change in temperature, in degrees? (Use a negative number for a fall.)
answer box
-6
Hint: 2 × (−3) = −6.
Question 5
What is −7 × (−10)?
−7 × (−10) = ?
answer box
70
Hint: Multiply the sizes, then use the sign rule: same signs positive, different signs negative.
Question 6
A change of −$12 is shared equally by 4 friends. What is each friend's change, in dollars?
answer box
-3
Hint: −12 ÷ 4 = −3.