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Math Grade 4-5 Answer Key

Adding and Subtracting Decimals

Practice lining up decimal points and finding sums and differences

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Adding and Subtracting Decimals

Practice lining up decimal points and finding sums and differences

Math - Grade 4-5

Instructions: Read each problem carefully. Line up the decimal points before you add or subtract. Show your work in the space provided.
  1. 1

    Find the sum: 3.4 + 2.5

    Write the numbers one under the other so the decimal points match.

    The sum is 5.9. Line up the decimal points and add the tenths and ones.
  2. 2

    Find the difference: 7.8 - 4.2

    The difference is 3.6. Subtract the tenths and ones after lining up the decimal points.
  3. 3

    Find the sum: 6.25 + 1.34

    Start adding from the rightmost place value.

    The sum is 7.59. Add the hundredths, tenths, and ones in order after lining up the decimal points.
  4. 4

    Find the difference: 9.50 - 2.17

    The difference is 7.33. Subtract carefully from right to left, using regrouping if needed.
  5. 5

    A notebook costs $4.75 and a pen costs $1.20. How much do they cost altogether?

    This is an addition problem because you are finding the total.

    They cost $5.95 altogether. Add 4.75 and 1.20 to find the total cost.
  6. 6

    You have $10.00 and spend $3.45 on a snack. How much money do you have left?

    You have $6.55 left. Subtract 3.45 from 10.00 to find the remaining amount.
  7. 7

    Find the sum: 0.6 + 0.27

    Adding a zero to the end of a decimal does not change its value.

    The sum is 0.87. Write 0.6 as 0.60 so the place values line up correctly.
  8. 8

    Find the difference: 5.00 - 0.86

    The difference is 4.14. Regroup as needed when subtracting the hundredths and tenths.
  9. 9

    A rope is 8.4 meters long. You cut off 2.35 meters. How much rope is left?

    Rewrite 8.4 as 8.40 before subtracting.

    There are 6.05 meters of rope left. Subtract 2.35 from 8.40 after lining up the decimal points.
  10. 10

    Find the sum: 12.08 + 3.7

    The sum is 15.78. Write 3.7 as 3.70 so the decimal places line up.
  11. 11

    Find the difference: 14.2 - 6.95

    Make sure both numbers have the same number of decimal places before subtracting.

    The difference is 7.25. Rewrite 14.2 as 14.20 and subtract carefully.
  12. 12

    Mia ran 1.75 miles on Monday and 2.5 miles on Tuesday. How many miles did she run in all?

    Mia ran 4.25 miles in all. Add 1.75 and 2.50 to find the total distance.
  13. 13

    A bottle holds 3.00 liters of water. If 1.48 liters are poured out, how much water remains?

    This is a subtraction problem because part of the water was removed.

    There are 1.52 liters remaining. Subtract 1.48 from 3.00 to find the amount left.
  14. 14

    Find the sum: 0.99 + 4.06

    The sum is 5.05. Add the hundredths, tenths, and ones after lining up the decimal points.
  15. 15

    Find the difference: 20.00 - 7.89

    Write zeros in the decimal places to help with regrouping.

    The difference is 12.11. Subtract 7.89 from 20.00 carefully, using regrouping across place values.
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