• All non zero digits are significant.
• The zeros to the right of the decimal point or zeros between two non-zero digits are significant.
• Zeros to the left of the first non-zero digit in a number smaller than one are not significant.
• In addition or subtraction, the result should be mentioned in the same number of decimal place as that of the term with the least decimal places.
• In multiplication and division, the result should be mentioned in same number of significant figures as the least precise term used in calculation.