CBSE Tuts

CBSE Maths notes, CBSE physics notes, CBSE chemistry notes

Addition and Subtraction-Decimal Numbers

Addition and Subtraction-Decimal Numbers:

Step 1) For adding or subtracting decimal numbers, write all the decimal numbers with equal number of decimal places i.e., convert them into like decimals. Add zeros at the end if necessary in order to convert them into like decimals.
For example, for adding 2.321 and 4.6, write the numbers as 2.321 and 4.600.

Step 2) Arrange the decimal numbers one below the other in such a way that the decimal points of all the numbers fall exactly one below the other i.e., in the same column.

Step 3) Add or subtract the decimal numbers treating them as ordinary numbers, ignoring the decimal points.

Step 4) After calculating the answer, put the decimal point exactly below the other decimal points i.e., in the same column.

In subtraction sums, the larger number(the minuend) should have at least the same number of decimal places as the smaller number. For this you may have to put in zeroes at the end of its decimal part.
When you round to 1 decimal place, you inspect the hundredths integer.

Addition and Subtraction-Decimal Numbers Example 1:

 

Find 26.79 + 0.4085 + 4 + 528.254.

Solution:

addition-of-decimals1

Addition and Subtraction-Decimal Numbers Example 2:

Add Rs 37.50, Rs 208.75 and Rs 326.

Solution:

addition-of-decimals2

Addition and Subtraction-Decimal Numbers Example 3:

 

Subtract .508 from 83.5.

Solution:  83.5 –> 83.500 Now, both numbers have 3 digits after the decimal point.

subtraction-of-decimals1

Addition and Subtraction-Decimal Numbers Example 4:

 

Find Rs 4 – Rs 2.25.

Solution:

subtraction-of-decimals2