Subtracting decimals - 1 | Year 6 Mathematics PDF Download

Subtracting Decimals

Subtracting decimals using the column method is similar to subtracting whole numbers. The key is to align the decimal points so that the place values match.

Let's explore this method with some examples:

Examples

Example 1: What is 145.2 – 134.19?
Sol: First, ensure both numbers have the same number of decimal places and align the decimal points.
Starting from the hundredths column, begin subtracting.
Since you cannot subtract 9 hundredths from 0 hundredths, exchange 1 tenth for 10 hundredths and adjust the number of tenths accordingly.
Continue with the subtraction.
No further exchanges are needed, so proceed to subtract the remaining digits.
Therefore: 145.2 - 134.19 = 11.01

Example 2: What is 12.34 – 10.5?
Sol: Ensure both numbers have the same number of digits after the decimal point. For 10.5, which has one digit after the decimal point, we can represent it as 10.50 to match the two digits after the decimal in 12.34.
Start subtracting from the hundredths column.
Since you can't subtract 5 tenths from 3 tenths, you need to exchange (or borrow) from the ones column.
Exchange 1 whole unit (1 one) for 10 tenths. Now you have 13 tenths.
Subtract 5 tenths from 13 tenths.
After the exchange, remember to adjust the number of ones accordingly.
Continue subtracting the remaining digits straightforwardly.
So, 12.34 - 10.50 = 1.84