Robinson Tuition
Year 8 · Key Stage 3 · free KS3 maths worksheet

Rounding and estimating

12 original questions, 26 marks. Type your answers below for an instant mark and a score (algebra in any equivalent form, e.g. 2sqrt(3) or 2√3), or print the worksheet, mark it with the answers sheet, and use the solutions to see every step written out by hand.

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The questions

1

Write the number 12.86 correct to 1 decimal place.

1 mark
Show answer
12.9
2

Write the number 3.472 correct to 2 decimal places.

1 mark
Show answer
3.47
3
  1. Write 7.0849 correct to 3 decimal places.
  2. Mia rounds 2.4967 to 2 decimal places. She writes 2.5
    Explain why Mia's answer is not fully correct.
2 marks
Show answer
a) 7.085 b) It should be 2.50 - the zero must be written to show 2 decimal places
4
  1. Write the number 4738 correct to 2 significant figures.
  2. Write the number 0.05372 correct to 2 significant figures.
2 marks
Show answer
a) 4700 b) 0.054
5

Write each number correct to 3 significant figures.

  1. 0.004078
  2. 39 962
  3. 6.996
3 marks
Show answer
a) 0.00408 b) 40000 (accept 40 000) c) 7.00
6

By rounding each number to 1 significant figure, work out an estimate for

(587 + 214) ÷ 3.9

2 marks
Show answer
200
7

Work out an estimate for the value of

48.7 × 6.120.216

You must round each number to 1 significant figure.

3 marks
Show answer
1500
8

The mass of a cat is 8.3 kg, correct to 1 decimal place.

Complete the error interval for the mass, w kg, of the cat.

....... ≤ w < .......

2 marks
Show answer
8.25 ≤ w < 8.35
9
  1. A number n is rounded to 1 significant figure. The result is 30
    Write down the error interval for n.
  2. Kai gives his age in whole years by truncating. He says he is 13
    Write down the error interval for Kai's exact age, a years.
2 marks
Show answer
a) 25 ≤ n < 35 b) 13 ≤ a < 14
10

A number x is 470, correct to 2 significant figures.

Complete the error interval for x.

....... ≤ x < .......

2 marks
Show answer
465 ≤ x < 475
11

The height of a sunflower is 160 cm, correct to the nearest 10 cm.

Ollie says, "The sunflower could be 165 cm tall."

Is Ollie correct? Give a reason for your answer.

2 marks
Show answer
No. The error interval is 155 ≤ h < 165, and 165 cm would round to 170 cm
12

Marco is building a fence.

He buys 28 fence panels costing £19.75 each.

He also buys a tin of paint costing £41.80

By rounding each number to 1 significant figure, work out an estimate for the total amount Marco pays.

4 marks
Show answer
£640

Your score

Answer the questions above and your score appears here.

Every question here is original and written by Robinson Tuition. It follows the Key Stage 3 programme of study; Year 9 sheets end with extension questions for top sets.

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