Virginia SOL Math / Grade 4 / Computation & Estimation

4.CE.4

Add & Subtract Decimals

What you'll learn

  • Estimate sums and differences of decimals through thousandths
  • Add and subtract decimals by lining up place values
  • Solve problems in context, including money

Words to know

Decimal point —
the dot that separates ones from tenths
Line up —
stack decimals so the decimal points match
Estimate —
a close, reasonable answer using rounding
Sum —
the answer to an addition problem
Difference —
the answer to a subtraction problem

Why it matters Adding and subtracting decimals lets us handle money and measurements accurately, like totaling a bill or finding change.

Worked examples

Model ItI do

Find 2.3 + 1.45.

Line up the decimal points and write 2.30 so both have hundredths. Add: 2.30 + 1.45 = 3.75. So 2.3 + 1.45 = 3.75.

Try It TogetherWe do

You have $5.00 and spend $2.65. How much is left?

Line up and subtract: 5.00 - 2.65 = 2.35. So you have $2.35 left.

Now YouYou do

Find 0.75 + 0.6.

Write 0.60 so both have hundredths, line up the decimal points, and add. Check your answer in the back.

Practice

Mastered 0 of 11

Warm-up

Ease in with the basics.

  1. 1.Find 1.2 + 1.5.

  2. 2.Find 3.6 - 1.2.

  3. 3.Find 0.5 + 0.3.

On Level

The core Quick Check from the book.

  1. 1.Find 3.4 + 2.8.

  2. 2.Find 6.5 - 1.75.

  3. 3.Find 0.125 + 0.5.

  4. 4.You buy items for $3.20 and $4.55. What is the total?

  5. 5.Find 10.0 - 4.35.

Challenge

Stretch your thinking.

  1. 1.Find 12.65 + 8.9.

  2. 2.Find 7.008 + 0.492.

  3. 3.You pay for a $6.75 book and a $3.49 pen with a $20 bill. How much change do you get?