Significant figures rules and properties

What are significant figures?
Significant figures are important and interesting figures. Significant figure is the first non – zero digit of the number.
Rules of Significant figures
Following are the significant digits rules: -
1. Leading zeros in a number are not the significant figures. For example 0.008 has only one significant figure and that is 8.
2. Zeroes which are imbedded in between are always significant figures. For example, 24.07 have four significant figures.
3. If the decimal point is specified then only the trailing zeros are significant figures. For example, 400.00 have five significant figures and 400 has only one significant figure and that is 4.

Learn more about Definite Integral Examples also for better understanding.
Properties of Significant figures
1. Adding and Subtracting Significant figures:
Adding Significant figures - When the two numbers are added, the number of decimal places of the sum is always equal to the least number of decimal places in any of the numbers added.

Subtracting Significant figures - When the two numbers are subtracted, the number of decimal places of the difference is always equal to the least number of decimal places in any of the numbers subtracted.

2. Multiplication and Division of Significant figures:
Multiplying significant figures - When the two numbers are multiplied, the number of decimal places of the product is always equal to the least number of decimal places in any of the numbers multiplied.
Dividing significant figures - When the two numbers are divided, the number of decimal places of the product is always equal to the least number of decimal places in any of the numbers divided.

3. Rounding Significant figures: We should round off the figures if we have too many significant digits. We can round off any number using either of two ways: -
• If digit is smaller than 5 then the digit remains unchanged, such as 2.43 can be rounded off to 2.4
• If the digit is greater than 5 or then we should drop that digit and add one to the preceding digit, such as 2.47 can be rounded off to 2.5