Significant Figures Examples
Worked examples by category — whole numbers, decimals, operations, and more. Each answer includes the rule applied.
Quick reference examples
10 common examples with answers and reasons.
Leading zeros not significant. Trailing zero after decimal is.
All trailing zeros after decimal are significant.
Trailing zeros ambiguous without decimal point.
Multiplication — 2 sf from 2.1.
Addition — 1 d.p. from 0.3.
Captive zero between 3 and 5 is significant.
Only the 5 is significant.
Trailing zeros after decimal are always significant.
Division — 2 sf from 2.0.
Subtraction — 2 d.p. from 8.40.
Browse by category
Whole numbers
Integers with trailing zeros — covers ambiguity rules.
Decimals
Numbers with decimal points — trailing zeros are always significant here.
Leading zeros
Decimals with leading zeros — only count from the first non-zero digit.
Operation examples
➕ Addition & Subtraction
0.3 has 1 d.p.
1.002 has 3 d.p.
100.0 has 1 d.p.
✖️ Multiplication & Division
2.1 has 2 sf
2.0 has 2 sf
0.01 has 1 sf
All number-specific examples
100
1 significant figure (minimum)
Trailing zeros in whole numbers without a decimal point are ambiguous
100.00
5 significant figures
Trailing zeros after a decimal point are always significant
0.00340
3 significant figures
Leading zeros are never significant
500
1 significant figure (minimum)
Trailing zeros in whole numbers without a decimal point are ambiguous
4500
2 significant figures (minimum)
Non-zero digits are always significant
0.0005
1 significant figure
Leading zeros are never significant
1.2300
5 significant figures
Trailing zeros after a decimal point are always significant
10
1 significant figure (minimum)
Trailing zeros in whole numbers without a decimal point are ambiguous
1000
1 significant figure (minimum)
Trailing zeros in whole numbers without a decimal point are ambiguous
0.010
2 significant figures
Leading zeros are never significant