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Year 7 · Maths · Negative numbers · Lesson 3

Negatives, BIDMAS and substitution

Use the order of operations with negative numbers, and substitute negative values into expressions, including powers.

Whiteboard video lesson: Negatives, BIDMAS and substitution

20-minute video lesson

Teaching, worked examples and 20 practice questions solved step by step.

Watch free for a month

What your child will learn

  • Use BIDMAS with negatives
  • Calculate powers of negatives
  • Substitute negative values
  • Use brackets correctly
  • Solve problems with negatives

The method

  1. Follow BIDMAS.
  2. Use the sign rules at each step.
  3. Put negative values in brackets when substituting.
  4. (−n)² is positive.

Key words: BIDMAS, negative, substitute, brackets, power.

Worked examples

The first three practice questions from the lesson, with every step.

Question 1

Work out −5 + 2 × 3.

  1. Step 1: 2 × 3 = 6
  2. Step 2: −5 + 6 = 1

Answer: 1

Question 2

Work out 8 + (−2) × 5.

  1. Step 1: (−2) × 5 = −10
  2. Step 2: 8 + (−10) = −2

Answer: −2

Question 3

Work out −6 × (−2) − 4.

  1. Step 1: −6 × (−2) = 12
  2. Step 2: 12 − 4 = 8

Answer: 8