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4MA1/1F Jun 2019, Question 21: Standard Form

Pearson Edexcel International GCSE Mathematics A 4MA1 · Paper 1F (Foundation) · Calculator · 4 marks

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The question, in short

Convert between standard form and ordinary numbers, then evaluate an expression involving numbers in standard form.

Summarised in our own words. Use the official paper for the exact wording and any diagrams.

Part (a) · 1 mark

Write 5.7 × 10⁶ as an ordinary number.

  1. 15.7 × 10⁶ means 5.7 × 1 000 000
  2. 2Move the digits 6 places to the left
  3. 35.7 × 10⁶ = 5 700 000

Answer5 700 000

Part (b) · 1 mark

Write 0.004 in standard form.

  1. 1Standard form needs a number between 1 and 10 multiplied by a power of 10
  2. 20.004 = 4 ÷ 1000
  3. 31 ÷ 1000 = 10⁻³
  4. 40.004 = 4 × 10⁻³

Answer4 × 10⁻³

Part (c) · 2 marks

Work out (2 × 10⁴ + 3 × 10⁵) ÷ (6.4 × 10⁻²).

  1. 12 × 10⁴ = 20 000 and 3 × 10⁵ = 300 000
  2. 220 000 + 300 000 = 320 000, which is 3.2 × 10⁵
  3. 36.4 × 10⁻² = 0.064
  4. 4320 000 ÷ 0.064 = 5 000 000

Answer5 000 000

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