iGCSE Mathematics (0580) - C1.3 Powers and roots- Exam Style Questions Paper 3- New Syllabus
Question
(a) Find the value of
(i) $\sqrt{1.96}$
(ii) $17^3$
(iii) $-0.8 \times -1.2$
(b) Write these numbers in order, starting with the smallest.
$\frac{11}{19} \quad 58\% \quad \frac{27}{47} \quad 0.574$
Most-appropriate topic codes (Cambridge IGCSE Mathematics 0580):
• C1.5 Ordering (b)
▶️ Answer/Explanation
(a)
(i) Compute the square root directly: $\sqrt{1.96} = 1.4$
(ii) Calculate the cube: $17 \times 17 \times 17 = 4913$
(iii) Multiply the two negative decimals (result will be positive): $-0.8 \times -1.2 = 0.96$
✅ Answers: (i) $1.4$, (ii) $4913$, (iii) $0.96$
(b)
Convert all numbers to decimals for easy comparison:
$\frac{11}{19} \approx 0.5789$
$58\% = 0.58$
$\frac{27}{47} \approx 0.5744$
$0.574$
Comparing these: $0.574 < 0.5744 < 0.5789 < 0.58$.
✅ Answer: $0.574 < \frac{27}{47} < \frac{11}{19} < 58\%$
(a) From the list of numbers: 6, 7, 10, 12, 18, 49, 63, write down:
(i) a factor of 21
(ii) a square number
(iii) a prime number
(b) Find the value of:
(i) the cube root of 1728
(ii) \(2^5\)
(iii) \(5^0\)
(iv) \(36^{\frac{1}{2}}\)
(c) Put one pair of brackets into this calculation to make it correct:
$$3 \times 2 – 6 – 2 \div 2 = 4$$
(d) Find the lowest common multiple (LCM) of 30 and 68.
▶️ Answer/Explanation
(a)(i) Ans: 7
Factors of 21: 1, 3, 7, 21. From the list, only 7 is present.
(a)(ii) Ans: 49
Square numbers in list: 49 (since \(7 \times 7 = 49\)).
(a)(iii) Ans: 7
Prime numbers in list: 7 (only divisible by 1 and itself).
(b)(i) Ans: 12
\(\sqrt[3]{1728} = 12\) because \(12 \times 12 \times 12 = 1728\).
(b)(ii) Ans: 32
\(2^5 = 2 \times 2 \times 2 \times 2 \times 2 = 32\).
(b)(iii) Ans: 1
Any non-zero number to the power of 0 is 1: \(5^0 = 1\).
(b)(iv) Ans: 6
\(36^{\frac{1}{2}} = \sqrt{36} = 6\).
(c) Ans: \(3 \times 2 – (6 – 2) \div 2 = 4\)
Working: \(3 \times 2 – (6 – 2) \div 2 = 6 – 4 \div 2 = 6 – 2 = 4\)
(d) Ans: 1020
Prime factors: \(30 = 2 \times 3 \times 5\) \(68 = 2^2 \times 17\) LCM = \(2^2 \times 3 \times 5 \times 17 = 1020\)
