0580/31 May/Jun 2023, Question 1: Reciprocals
Cambridge IGCSE Mathematics 0580 · Paper 31 (Core) · Calculator · 14 marks
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The question, in short
Answer a set of short number questions covering place value, roots, reciprocals, powers, signed arithmetic, order of operations, irrational numbers, and LCM/HCF.
Summarised in our own words. Use the official paper for the exact wording and any diagrams.
Part (a) · 1 mark
Write forty thousand and thirty-three using digits.
- 1Forty thousand = 40 000, plus thirty-three = 33
- 240 000 + 33 = 40033
Answer40033
Part (b) · 1 mark
Evaluate the cube root of 729.
- 19 × 9 × 9 = 729
- 2∛729 = 9
Answer9
Part (c) · 2 marks
Find the reciprocal of 7/9 as a decimal rounded to 3 decimal places.
- 1Reciprocal of 7/9 = 9/7
- 29 ÷ 7 = 1.28571…
- 3≈ 1.286 (3 d.p.)
Answer1.286
Part (d) · 2 marks
Calculate 6⁵ ÷ 3⁴.
- 16⁵ = 7776 and 3⁴ = 81
- 27776 ÷ 81 = 96
Answer96
Part (e) · 1 mark
Work out (−9) × (−7) ÷ (−3).
- 1(−9) × (−7) = 63
- 263 ÷ (−3) = −21
Answer−21
Part (fi) · 1 mark
Evaluate 11 + 9 × 5 − 4 using the correct order of operations.
- 1Multiply first: 9 × 5 = 45
- 211 + 45 − 4 = 52
Answer52
Part (fii) · 1 mark
Evaluate (11 + 9) × 5 − 4, respecting the brackets.
- 1Brackets first: 11 + 9 = 20
- 220 × 5 − 4 = 100 − 4 = 96
Answer96
Part (g) · 1 mark
From the given list, identify which value is irrational.
- 1√49 = 7, −0.67, 5/9 and 3.142 can all be written as fractions
- 2123 is not a square number, so √123 cannot be written as a fraction
- 3Irrational number: √123
Answer√123
Part (hi) · 2 marks
Find the lowest common multiple of 24 and 104.
- 124 = 2 × 2 × 2 × 3 = 2³ × 3
- 2104 = 2 × 2 × 2 × 13 = 2³ × 13
- 3LCM = 2³ × 3 × 13 = 312
Answer312
Part (hii) · 2 marks
Find the highest common factor of 24 and 104.
- 124 = 2³ × 3 and 104 = 2³ × 13
- 2Common factors: 2 × 2 × 2
- 3HCF = 8
Answer8
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Also searched as: 0580/31/M/J/23 · 0580_s23_qp_31 · 0580 s23 31 · question 1.
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