1.3 Calculating with decimals
9 exam questions worth 19 marks. Write your answer, open the mark scheme, then give yourself the marks you earned. Your answers are saved on this device.
0 / 19
Work out 15.7 + 4.38.
Mark scheme
M1: aligning the decimal points / 15.70 + 4.38; A1: 20.08
Model answer
15.70 + 4.38 = 20.08.
Work out 9 - 3.274.
Mark scheme
M1: 9.000 - 3.274; A1: 5.726
Model answer
9.000 - 3.274 = 5.726.
What is 0.6 \times 0.5?
Choose one answer.
Correct Not quite: the answer is 0.3
Mark scheme
B: 0.3
Model answer
0.3 (B). 6 × 5 = 30, and there are two decimal places, so 0.30 = 0.3.
Work out 3.6 \times 2.4.
Mark scheme
M1: 36 × 24 (864); M1: counting 2 decimal places; A1: 8.64
Model answer
36 × 24 = 864. There are two decimal places, so 3.6 × 2.4 = 8.64.
Work out 8.4 \div 0.07.
Mark scheme
M1: 840 ÷ 7 (multiply both by 100); A1: 120
Model answer
Multiply both numbers by 100: 840 ÷ 7 = 120.
Work out 12.6 \div 5.
Mark scheme
M1: correct division method; A1: 2.52
Model answer
12.6 ÷ 5 = 2.52.
Given that 48 \times 25 = 1200, write down the value of (a) 4.8 \times 2.5 (b) 120 \div 2.5
Mark scheme
B1: 12; B1: 48
Model answer
(a) 4.8 × 2.5 is 100 times smaller than 1200, so 12. (b) 120 ÷ 2.5 = 1200 ÷ 25 = 48.
Ali buys 4 packets of biscuits at £2.35 each and 2 bottles of juice at £1.79 each. He pays with a £20 note. How much change does he get?
Mark scheme
M1: 4 × 2.35 = 9.40 or 2 × 1.79 = 3.58; M1: 20 - total (12.98); A1: £7.02
Model answer
4 × 2.35 = 9.40 and 2 × 1.79 = 3.58, total 12.98. Change = 20 - 12.98 = £7.02.
Rob says that 0.2 \times 0.3 = 0.6. Explain Rob's mistake and write the correct answer.
Mark scheme
B1: he has not counted the decimal places (2 and 3 are one decimal place each, so the answer needs two); B1: 0.06
Model answer
Rob multiplied 2 × 3 = 6 but forgot to put the decimal point back. There is one decimal place in each number, so the answer has two decimal places: 0.06.
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