In this activity, we will learn about the subtraction of numbers with decimals.

Example

Find the difference between  17.5  and 2.75.

Answer

Finding the difference means subtracting, so we need to work out 17.5 - 2.75

Step 1. Line up the decimal points and add zeros when needed, next to the 17.50

Step 2. Subtract, starting with the hundredths place. We need to exchange, so 5 in the tenths place becomes 4 and 0 in the hundredths place becomes 10. Subtract 10 - 5 = 5.

Step 3. Move to the tenths place and exchange with the ones place (to the left of the decimal point), so the 7 becomes 6 and the 4 in the tenths place becomes 14. Subtract 14 - 7 = 7.

Step 4. Move to the ones place, to the left of the decimal. Subtract 6 - 2 = 4 and then in the tens place, 1 - 0 = 1.

The answer is 14.75

Subtract as normal, but remember to line up the decimal points so that the place value in the answer is correct. 

Let's have a go at some questions now.