CAIE IGCSE Mathematics Core Estimating Calculations

Practise rounding every value to one significant figure, displaying the substituted calculation and judging whether an estimate is high or low.

Syllabus
2028–2030
Objective
C1.9.2
Level
Core

Exam points

  • round each number to one significant figure before substituting it into the calculation
  • show the rounded expression and follow the original brackets and operation order
  • decide whether an estimate is above or below the exact value from the rounding directions

C1.9.2 Make estimates for calculations involving numbers, quantities and question 1

[Maximum number: 2]

By writing each number in the calculation correct to 1 significant figure, find an estimate for the value of

2.7×42.48.6−4.3\frac{2.7 \times 42.4}{8.6-4.3}

You must show all your working.

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