Add and Subtract Decimals

Add and Subtract Decimals

What students learn

Students learn to line up decimal points and keep place values matched when adding or subtracting. Open with Add Decimals: Line Up the Decimal Points to see the setup.

Why it matters

This habit keeps decimal computation accurate in shopping, measurement, and science. Review Subtract Decimals: Add Zeros When Needed to see how a zero can keep the columns aligned.

Learn the idea

Once the decimal points are lined up, students can add or subtract the columns just as they would with whole numbers. Finish with Add and Subtract Decimals: Check the Answer and see whether the result is reasonable.

Try it

Ask the student to solve 4.6 + 2.35, 8.2 - 3.75, and 10.04 + 0.6. After each answer, have them explain which places changed.

Parent guide

Keep a place-value chart nearby if the student loses track of the columns. Ask them to read the answer in words and compare it to the starting numbers.