Ordering and Rounding Numbers

IGCSE Edexcel Mathematics
1.1 Ordering
1.2 Rounding
Key Concepts: Order numbers using <, >, =. Round to decimal places (count digits after decimal point). Round to significant figures (count from first non-zero digit). Estimate calculations by rounding.

Section A: Ordering Numbers

1. Arrange in ascending order: [3]
(a) 0.45, 0.405, 0.5, 0.04
(b) -7, 3, -2, 0, -10
(c) 23, 0.65, 710, 68%

Section B: Rounding to Decimal Places

2. Round to the given number of decimal places: [3]
(a) 4.578 to 1 d.p.
(b) 12.3456 to 2 d.p.
(c) 0.09872 to 3 d.p.

Section C: Significant Figures

3. Round to the given number of significant figures: [4]
(a) 4567 to 2 s.f.
(b) 0.004582 to 2 s.f.
(c) 3.0456 to 3 s.f.
(d) 299,876 to 1 s.f.

Section D: Estimation

4. Estimate the value by rounding to 1 significant figure: [3]
(a) 48.7 × 3.2
(b) 197 ÷ 4.8
(c) 52.3 × 8.9 ÷ 2.1
Total marks: 13

Mark Scheme

1. (a) 0.04, 0.405, 0.45, 0.5 [1]; (b) -10, -7, -2, 0, 3 [1]; (c) 0.65, 2/3, 68%, 7/10 (or 0.65, 0.667, 0.68, 0.7) [1]
2. (a) 4.6 [1]; (b) 12.35 [1]; (c) 0.099 [1]
3. (a) 4600 [1]; (b) 0.0046 [1]; (c) 3.05 [1]; (d) 300,000 [1]
4. (a) 50 × 3 = 150 [1]; (b) 200 ÷ 5 = 40 [1]; (c) 50 × 9 ÷ 2 = 225 [1]