Adding and subtracting decimals

What they’re learning

Your child is adding and subtracting decimals, especially to hundredths. Correct place-value alignment is more important than simply “lining up digits.”

Explain it to my child

Line up the decimal points because that lines up ones with ones, tenths with tenths, and hundredths with hundredths.

Try it together

Use pretend money amounts, since dollars and cents naturally model hundredths. Add two prices and calculate change from $20 or $50.

Practice

1. 3.45 + 2.70 = ?
2. 10.00 - 6.38 = ?
3. 8.6 + 1.27 = ?
4. 12.05 - 0.9 = ?
5. Estimate 19.78 + 5.12 before calculating.

Check understanding

• Does your child align decimal places correctly?
• Can they use money or estimation to check whether an answer is sensible?