Adding and Subtracting Decimals
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Objective
I can add and subtract decimals using models and strategies based on place value.
Part 1 of 4
Warm-up video
Math with Mr. J · 9:06Vetted channel
We don't generate video — this one is by Math with Mr. J on YouTube. The practice questions and exit ticket below were drafted by AI for this objective, and every question is editable in the teacher guide.
Part 2 of 4
Key concepts
3 concepts
- 1
When adding or subtracting decimals, the first step is to line up the decimals to ensure that all the places are lined up correctly.
- 2
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.
- 3
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.
Part 3 of 4
Practice
8 questions
When adding or subtracting decimals, what is the most important first step?
Explain why using placeholder zeros to the right of a decimal does not change the value of the number.
Part 4 of 4
Exit ticket
Quick comprehension check
“Solve 35.6 + 18.74. Show your work, lining up the decimals and using a placeholder zero if needed.”
Sample answer included in the free materials
Get the materials
Teacher guide, student handout, and slides — free, in Google Docs format
Teacher Guide
Complete lesson plan with answer keys and alternate activities
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