How many significant figures does 10 have?
1 significant figure
The digits that count: 1
Written this way it is ambiguous. 10 could equally be read as 2 significant figures — the notation gives no way to tell. Counting the trailing zeros as not significant is the usual convention, but it is a convention, not a rule. Scientific notation removes the doubt.
Why
- →Every non-zero digit is significant.
- →Trailing zeros in a whole number with no decimal point are ambiguous. They are not counted here, which is the usual convention.