1.4 Order of operations and inverse operations
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
What is the value of 7 + 3 \times 4?
Choose one answer.
Correct Not quite: the answer is 19
Mark scheme
B: 19
Model answer
19 (B). Multiply first: 3 × 4 = 12, then 7 + 12 = 19.
Work out 20 - 3^2 \times 2.
Mark scheme
M1: 3² = 9 and 9 × 2 = 18; A1: 2
Model answer
3² = 9, 9 × 2 = 18, 20 - 18 = 2.
Work out (12 - 4)^2 \div 16.
Mark scheme
M1: (8)² = 64; A1: 4
Model answer
(12 - 4)² = 8² = 64 and 64 ÷ 16 = 4.
Work out \sqrt{25 + 11}.
Mark scheme
M1: √36; A1: 6
Model answer
25 + 11 = 36 and √36 = 6.
Work out \dfrac{18 + 6}{10 - 4}.
Mark scheme
M1: 24 and 6 (evaluating top and bottom); A1: 4
Model answer
The top is 24 and the bottom is 6, so the answer is 24 ÷ 6 = 4.
Write down the reciprocal of (a) 8 (b) \frac{3}{5} (c) 0.5
Mark scheme
B1: \frac{1}{8}; B1: \frac{5}{3}; B1: 2
Model answer
(a) 1/8. (b) 5/3. (c) 1 ÷ 0.5 = 2.
Given that 36 \times 14 = 504, write down the value of (a) 504 \div 14 (b) 504 \div 36.
Mark scheme
B1: 36; B1: 14
Model answer
(a) 36 (b) 14, because division is the inverse of multiplication.
A number is multiplied by 4 and then 7 is subtracted. The answer is 29. Work out the number.
Mark scheme
M1: 29 + 7 (reverse the subtraction); M1: ÷ 4; A1: 9
Model answer
Work backwards: 29 + 7 = 36 and 36 ÷ 4 = 9. Check: 9 × 4 - 7 = 29.
Amy says that -5^2 = 25. Is Amy correct? Explain your answer.
Mark scheme
B1: No; B1: -5² means -(5²) = -25 (the power is done before the negative sign) / (-5)² = 25 needs brackets
Model answer
Amy is not correct. The power is worked out first, so -5² = -(5 × 5) = -25. To get 25 you would need brackets: (-5)² = 25.
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