Adding and Subtracting Decimals
Learning Objective
I can add and subtract decimals using models and strategies based on place value.
Key Concepts
When adding or subtracting decimals, the first step is to line up the decimals to ensure that all the places are lined up correctly.
Placeholder zeros can be added to the right of a decimal without changing its value; this can help to line up the numbers and avoid mistakes when adding or subtracting.
When subtracting decimals, remember to borrow if the top digit is smaller than the bottom digit; avoid the common mistake of just dropping the bottom number.
Practice Questions
This lesson includes 8 practice questions to reinforce learning.
View questions preview
1. When adding or subtracting decimals, what is the most important first step?
2. Explain why using placeholder zeros to the right of a decimal does not change the value of the number.
3. Solve: 5.7 + 2.35. Show your work, including any placeholder zeros you use.
...and 5 more questions
Educational Video
Adding and Subtracting Decimals: A Step-By-Step Review | How to Add and Subtract Decimals
Math with Mr. J