Adding and subtracting decimals follows exactly the same procedure as adding and subtracting whole numbers. However, decimals require a better understanding of place value.
The column method with decimals
Adding and subtracting using the column method also works for decimals. However, there are a few things to take note of.
Reminder when using the column method with decimals
Remember to line up all the numbers that come after the decimal point as well - so the tenths, hundredths, thousandths and so on.
Use zero as a placeholder if one number has fewer place values than the other.
It is possible to "carry over a one" or "borrow a one" from the units digit to the tenths digit - the decimal point isn't a barrier!
The decimal point should be aligned under the answer line also.
Example: subtraction
What is 2.198−0.52?
Align the two numbers as normal, making sure to line up the decimal point and all digits after the point.
Note how 0.52 has no thousandths digit, but 2.198 does. So, add zero as a placeholder so both numbers have the same amount of digits. 0.52 is hence written as 0.520.
2.198−0.52=1.678
Example: addition
What is 12.34+9.75?
12.34+9.75=22.09
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Learn with Basics
Learn the basics with theory units and practise what you learned with exercise sets!
Length:
Unit 1
Multi-step problems with addition and subtraction
Unit 2
Addition and subtraction using the column method
Jump Ahead
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Optional
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Unit 3
Adding and subtracting decimals
Final Test
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FAQs - Frequently Asked Questions
How do you add and subtract decimals with the column method?
Align the numbers and the decimal point. Add in any zeroes as a placeholder if necessary, and perform the addition/subtraction like normal.
How do you add and subtract decimals?
Add and subtract decimals using the column method.
