Printable · GCSE Foundation · ages 14-16
Estimation and checking worksheet — GCSE Foundation
Fifteen questions on "estimation and checking" — DfE statement N14. Print it, or print three versions so neighbours cannot copy by letter; the key gives the letter for each version.
Non-calculator
Estimation and checking worksheet — GCSE Foundation
MathsUKwww.geekhero.co.uk
- 1.Amelia has 49 boxes of apples with 21 apples in each box. Work out an estimate for the total number of apples, by rounding each number to 1 significant figure.
- 2.Work out an estimate for 588 ÷ 31, by rounding each number to 1 significant figure.
- 3.Tickets to a theme park cost £38.50 for an adult and £19.75 for a child. A family estimates the total cost for 4 adults and 3 children, by rounding each ticket price to the nearest £5. Work out their estimate for the total cost.
- 4.Hannah works out 3.1 × 19.6 on her calculator and writes down 6.076. Work out an estimate for 3.1 × 19.6, by rounding each number to 1 significant figure.
- 5.Work out an estimate for 312 × 19, by rounding each number to 1 significant figure.
- 6.Work out an estimate for 6.8 × 41, by rounding each number to 1 significant figure.
- 7.A minibus can carry 16 passengers. A school is taking 179 pupils on a trip. By rounding 179 to the nearest 10, work out an estimate for the number of minibuses needed, given that the school cannot hire part of a minibus.
- 8.Work out an estimate for 397 ÷ 21, by rounding each number to 1 significant figure.
- 9.A shop assistant says that 7.2 × 3.9 = 56.16. Work out an estimate for 7.2 × 3.9, by rounding each number to the nearest whole number, to show that the assistant’s answer cannot be correct.
- 10.A school orders 187 packed lunches for a trip. Each packed lunch costs £4.85. The school has £900 to spend. By rounding each number to 1 significant figure, work out an estimate for the total cost and decide whether £900 is enough.
- 11.Amelia estimates 48 × 21 by working out 50 × 20 = 1,000. Work out whether her estimate is an under-estimate or an over-estimate, and by how much.
- 12.A spreadsheet shows that 812 − 397 = 315. Work out an estimate for 812 − 397, by rounding each number to the nearest 100, to check whether the spreadsheet's answer is reasonable.
- 13.Work out an estimate for 8,900 ÷ 29, by rounding each number to 1 significant figure.
- 14.Freya uses her calculator to work out 7² and writes down 14. Work out the correct value of 7².
- 15.Freya types 4² + 3² into her calculator and writes down 49. Work out the correct value of 4² + 3².
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