Addition and Subtraction of Decimals

 

Addition 

Adding decimals is a simple and same method of adding any other number.

To add decimals, we follow these steps:

1. Convert the given decimals to like decimals

1. Write the decimals in column in alignment with their place value such that decimal points are below each other and also the place values of the numbers i.e. tenths come under tenths, hundredths come under hundredths and so on.

1. Add as we add whole numbers.

1. Place the decimal point directly under decimal points.

 

The following examples will make this concept more clear

Example: Add 1.462 to 1.36

First, we convert the numbers to like decimals

i.e. 1.462 + 1.36 = 1.462 + 1.360

Now,

Example: Add 31.725, 0.475 and 5

First, we convert the numbers to like decimals

i.e. 31.725 + 0.475 + 5 = 31.725 + 0.475 + 5.000

Now,

 

Example: If English book cost $9.94, Mathematics book cost $0.31, Hindi book cost $0.99 and Science book cost $1.94. Find the total cost of all the books?

 

Solution:

Cost of English book = $9.94

Cost of Mathematics book = $0.31

Cost of Hindi book = $0.99

Cost of Science book = $1.94

To find the total cost, we add the cost of these books as-

Thus, the total cost of the books is $13.18.

 

 

Subtraction of Decimals

Like addition, subtraction of a decimal is also similar to the subtraction of whole numbers.

 

To subtract decimals, we follow these steps:

1. Convert the given decimals into like decimals

1. Arrange the like decimals in column as per their place values, with decimal point falling in one line and then subtract

Example: Subtract 1.362 from 1.97

First, we convert the numbers to like decimals

i.e. 1.97 – 1.362 = 1.970 – 1.362

Now,

 

Example: Subtract 51.962 from 77.27

First, we convert the numbers to like decimals

i.e. 77.27 – 51.962 = 77.270 – 51.962

Now,

Example: Bill’s father gave him $1.59. If he spent $0.32 on chocolates, how much money is left with him?

 

Solution: 

Amount Bill got from his father = $1.59

Amount he spent on chocolates = $0.32

Amount left with him = $1.59 – $0.32

Thus, amount left with him is $1.27