Work through the levels in order. Type your answer and press Check — open the worked solution if you get stuck. Answers like -6, 3/4 or 0.25 are typed exactly as shown.
Level 1 · Warm-up
1 How many significant figures in 0.0045?
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The 4 and the 5 → 2 significant figures.
2 How many significant figures in 2005?
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2, 0, 0, 5 → 4 significant figures.
3 Round 8642 to 2 significant figures.
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8600.
Level 2 · Core
4 Round 34567 to 3 significant figures.
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345 → 346, so 34600.
5 Round 0.08256 to 3 significant figures.
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825 → 826 (next digit 6), so 0.0826.
6 Round 2049 to 2 significant figures.
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2000.
Level 3 · Challenge
7 Write 34600 in scientific notation. (as a simplified expression)
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3.46 × 104 — and the 3 s.f. are now visible at a glance.
8 How many significant figures does 5.20 × 107 claim?
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5, 2 and the trailing 0 → 3.
9 A calculator shows 7.83625. Round to 3 significant figures.
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7.84.