Define significant figures:
Those digits in a number that are meaningful in terms of precision and accuracy are known as significant figures.
The larger the number of significant figures obtained in a measurement, the greater is the accuracy of the measurement and vice-versa.
Rules for Significant Figures
- All non-zero digits are significant.
198745 contains six significant digits. - All zeros that occur between any two non-zero digits are significant. For example,
108.0097 contains seven significant digits. - All zeros that are on the right of a decimal point and also to the left of a non-zero digit are never significant. For example,
0.00798 contained three significant digits. - All zeros that are on the right of a decimal point are significant, only if, a non-zero digit does not follow them. For example,
20.00 contains four significant digits. - All the zeros that are on the right of the last non-zero digit, after the decimal point, are significant. For example,
0.0079800 contains five significant digits. - All the zeros that are on the right of the last non-zero digit are significant if they come from a measurement. For example,
1090 contains four significant digits.