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GCSE · Number

1.7D Rounding: Fluency and Exam Drill

EDEXCEL Edexcel 1MA1 · Calculator allowed · about 35 minutes

Total Marks

Name: _______________________________ Date: ____ / ____ / ______

Answer ALL questions. Show all your working.

Round 274 to the nearest 10.

(Total for Question 1 is 1 mark)

Round 4,862 to the nearest 100.

(Total for Question 2 is 1 mark)

Round 15,648 to the nearest 1,000.

(Total for Question 3 is 1 mark)

Round 3.846 to 2 decimal places.

(Total for Question 4 is 1 mark)

Round 0.04687 to 3 decimal places.

(Total for Question 5 is 1 mark)

Round 82.56 to 1 significant figure.

(Total for Question 6 is 1 mark)

Round 0.007894 to 2 significant figures.

(Total for Question 7 is 1 mark)

A shop price is £24.95. Give a quick estimate of the price to 2 significant figures for a mental comparison.

(Total for Question 8 is 1 mark)

Calculate 46.8 x 3.25. Give your answer rounded to 2 decimal places. Then estimate the product by rounding each number to 1 significant figure and say whether your rounded answer is reasonable.

(Total for Question 9 is 3 marks)

Show that 0.3728 rounded to 3 significant figures is 0.373.

(Total for Question 10 is 2 marks)

A cylinder has radius 3.56 cm and height 12.4 cm. Calculate the volume in cubic centimetres. Give your answer to 3 significant figures. (Use π = 3.14159265...)

(Total for Question 11 is 3 marks)

A student multiplies 129.7 by 0.486 and writes 63.0 as the result. Use rounding to 2 significant figures to estimate the product and say whether 63.0 is a reasonable answer.

(Total for Question 12 is 2 marks)

A recipe needs 0.0375 kg of sugar per portion. How much sugar is needed for 280 portions? Give your answer rounded to 2 significant figures for shopping.

(Total for Question 13 is 3 marks)

A factory produced 12,642 items this week. Report this total rounded to the nearest 100.

(Total for Question 14 is 1 mark)

Show that 0.004679 rounded to 2 significant figures is 0.0047.

(Total for Question 15 is 2 marks)

Round 999.6 to the nearest 10 and to the nearest 100. Explain briefly why both answers may be the same.

(Total for Question 16 is 3 marks)

Mark scheme · 1.7D Rounding: Fluency and Exam Drill

Question 1

B1 270 cao
Answer: 270

Question 2

B1 4,900 cao
Answer: 4900

Question 3

B1 16,000 cao
Answer: 16000

Question 4

B1 3.85 cao
Answer: 3.85

Question 5

B1 0.047 cao
Answer: 0.047

Question 6

B1 80 cao
Answer: 80

Question 7

B1 0.0079 cao
Answer: 0.0079

Question 8

B1 £25 cao
Answer: 25

Question 9

M1 correct calculation of product, e.g. 46.8 x 3.25 = 152.1 or method shown
A1 152.10 cao
B1 estimation: 50 x 3 = 150 and conclusion that 152.10 is reasonable oe
Answer: 152.10

Question 10

M1 identify first 4 significant digits 3,7,2,8 and note the 4th digit 8 causes rounding up oe
A1 cso 0.373 cao
Answer: 0.373

Question 11

M1 use volume = π r² h with substitution π x 3.56² x 12.4
M1 carry out calculation to find volume = π x 157.15264 = 493.709... (or equivalent)
A1 494 cm³ to 3 s.f. cao
Answer: 494 cm³

Question 12

M1 estimate using 130 x 0.49 = 63.7 oe
A1 conclude 63.0 is reasonable as it is close to the estimate cao
Answer: Yes, reasonable (estimate 63.7)

Question 13

M1 multiply 0.0375 x 280 = 10.5 shown
A1 round 10.5 to 2 s.f. = 11.0 or 11 kg cao
B1 state this is suitable as a shopping estimate oe
Answer: 11 kg

Question 14

B1 12,600 cao
Answer: 12,600

Question 15

M1 identify first three significant digits 4,6,7 and note the 3rd digit 7 causes rounding up oe
A1 cso 0.0047 cao
Answer: 0.0047

Question 16

M1 nearest 10: 1,000 identified
M1 nearest 100: 1,000 identified
B1 explain that rounding crosses the threshold so both round up to 1,000 oe
Answer: nearest 10 = 1000; nearest 100 = 1000

Rounding: Fluency and Exam Drill - Worksheets, Questions and Revision