Addition of Decimals

Addition of Decimals

Decimals are fractional numbers. The decimal 0.3 is the same as the fraction 3/10. The number 0.78 is a decimal that represents 78/100.

Adding Decimals is just like adding other numbers.

Always line up the decimal points when adding decimals.

Remember to put the decimal point in the proper place in your answer.

The rules of adding decimal numbers are:

(i) Write the digits of the given numbers one below the other such that all the decimal points are in the same vertical line.

(ii) Add as we add whole numbers.

(iii) Put the decimal point of the sum vertically below the other decimal points.


To add decimals, follow these steps:

  • Write down the numbers, one under the other, with the decimal points lined up
  • Put in zeros so the numbers have the same length
  • Then add using column addition, remembering to put the decimal point in the answer.

Problem 1: Add 1.452 to 1.3

Problem 2: Subtracting: To subtract, follow the same method: line up the decimals, then subtract.

Example: What is 7.368 − 1.15?


Information Source: AAA Math