NumberKey Stage 3

Multiplying with negative numbers

Determine the sign of a product, including products with several negative factors.

  • Two factors with the same sign give a positive product. Different signs give a negative product.
  • For several non-zero factors, count the negative factors: an even count gives a positive product; an odd count gives a negative product.
  • Then multiply the sizes of the numbers. If any factor is zero, the product is zero.

Example 1

Two negative factors

Evaluate the expression.

Two negatives: even

Example 2

Three negative factors

Calculate the value of the expression.

Three negative factorsThe first two negatives give a positive

Remember
The odd/even rule counts negative factors, not the size of the numbers.

Your turn

Question 1

Calculate.

Check answer

One negative factor: negative.

Question 2

Calculate.

Check answer

One negative factor: negative.

Question 3

Calculate.

Check answer

Two negative factors: positive.

Question 4

Calculate.

Check answer

Three negative factors: negative.

Question 5

Calculate.

Check answer

Four negative factors: positive.

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