Integers · Multiply · 6.2

The sign rule.

Multiply the sizes, then set the sign: different signs give a negative product, same signs give a positive. −6 × 7 = −42.

01 / THE IDEA

See it work.

Watch the method

The sign rule

−6 × 7: 6 × 7 = 42, different signs → −42.

1 / 2
−6×7-6 \times 7
1

Multiply the sizes

Ignore the signs first: 6 × 7 = 42.

6×7=426 × 7 = 42
2

Decide the sign

Different signs → the answer is negative.

(−6)×7=−42(-6) × 7 = -42
02 / YOUR TURN

Practice until it feels automatic.

Your turn

Work it out.

Type a whole number — negatives allowed, e.g. -7.

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— / WHY IT WORKS

The idea underneath.

Size then sign

First multiply absolute values, then apply the sign rule. The order in which you multiply does not change the sign.

Why it works

Count first, then decide direction.

03 / WORKED EXAMPLES

From easy to tricky.

EX 1easy

Multiply -8 × 6

1

Multiply the sizes

Ignore the signs first: 8 × 6 = 48. 8 × 6 = 48

2

Decide the sign

Different signs → the answer is negative. (-8) × 6 = -48

EX 2medium

Multiply 8 × -8

1

Multiply the sizes

Ignore the signs first: 8 × 8 = 64. 8 × 8 = 64

2

Decide the sign

Different signs → the answer is negative. 8 × (-8) = -64

EX 3hard

Multiply -6 × 7

1

Multiply the sizes

Ignore the signs first: 6 × 7 = 42. 6 × 7 = 42

2

Decide the sign

Different signs → the answer is negative. (-6) × 7 = -42

04 / COMMON TRAPS

Where students slip.

Trap

Forgetting to set the sign.

Fix

Decide the sign after multiplying the sizes.

Trap

Thinking neg × pos is positive.

Fix

Different signs give a negative.

05 / QUIZ

Test yourself.

The Test

12 problems across three tiers. Auto-graded on submit. Hints and a full walkthrough on every question. Your work is saved on this device — sign in to keep it across devices.

0/12Answered
How to answerType just the value. Formatting won't trip you up — we ignore spaces, capital letters, commas, and subscript style, so t₁ = 5, d = 3 and t1=5,d=3 both count. For a list of numbers, separate them with commas (e.g. 3, 10, 17).
Core

Core (4)

C1

Multiply -8 × 6

Need a hint?
  • Multiply the sizes.
  • Different signs → negative.
C2

Multiply 7 × -9

Need a hint?
  • Multiply the sizes.
  • Different signs → negative.
C3

Multiply -4 × 3

Need a hint?
  • Multiply the sizes.
  • Different signs → negative.
C4

Multiply 12 × -1

Need a hint?
  • Multiply the sizes.
  • Different signs → negative.
Apply

Apply (4)

A1

Multiply 8 × -8

Need a hint?
  • Multiply the sizes.
  • Different signs → negative.
A2

Multiply -12 × 1

Need a hint?
  • Multiply the sizes.
  • Different signs → negative.
A3

Multiply 12 × -8

Need a hint?
  • Multiply the sizes.
  • Different signs → negative.
A4

Multiply 12 × -4

Need a hint?
  • Multiply the sizes.
  • Different signs → negative.
Extension

Extension (4)

E1

Multiply -6 × 7

Need a hint?
  • Multiply the sizes.
  • Different signs → negative.
E2

Multiply -11 × 9

Need a hint?
  • Multiply the sizes.
  • Different signs → negative.
E3

Multiply 4 × -9

Need a hint?
  • Multiply the sizes.
  • Different signs → negative.
E4

Multiply -8 × 2

Need a hint?
  • Multiply the sizes.
  • Different signs → negative.