Subtraction Within 20: Grade 1 Math Worksheet Answer Key – PDF Download

Grade 1 Subtraction Worksheet Answer Key: problems 1–5

Problem 1: Take away a picture

Start with 8. Take away 3. Count the grapes that are not crossed out: 5.

\(8-3=5\)

Problem 2: Ten frame take away

There are 9 counters in all. Four are crossed out. Five are left.

\(9-4=5\)

Problem 3: Find the differences

1. \(7-2=5\)
2. \(10-6=4\)
3. \(8-0=8\). Taking away 0 changes nothing.
4. \(6-6=0\). Taking away all leaves 0.

5, 4, 8, 0

Problem 4: Doubles help

1. \(5+5=10\), so \(10-5=5\).
2. \(7+7=14\), so \(14-7=7\).
3. \(9+9=18\), so \(18-9=9\).

5, 7, 9

Problem 5: Count back on a number line

Hop back one step at a time: 11, 10, 9, 8. You land on 8.

\(12-4=8\)

Grade 1 Subtraction Worksheet Answer Key: problems 6–10

Problem 6: Count back

Start at 15. Count back 3: 14, 13, 12.

\(15-3=12\)

Problem 7: Think addition with a bar

Ask: 7 plus what number makes 10? Count up from 7: 8, 9, 10. That is 3 counts. Check: \(7+3=10\).

\(10-7=3\)

Problem 8: Missing addend

Count up from 9 to 12: 10, 11, 12. That is 3 counts, so \(9+3=12\).

3, and \(12-9=3\)

Problem 9: Subtract by making a ten

Split 8 into 3 and 5. Take away 3 first: \(13-3=10\). Then take away 5: \(10-5=5\).

5, 5, 5

Problem 10: Fact family of three numbers

The whole is 13. The parts are 6 and 7. Write two addition and two subtraction sentences.

\(6+7=13\), \(7+6=13\), \(13-7=6\), \(13-6=7\)

Grade 1 Subtraction Worksheet Answer Key: problems 11–15

Problem 11: Write the missing sentence

The fourth sentence takes away the other part. Take away 5 from 14.

\(14-5=9\)

Problem 12: Use a related fact

The whole is 15. Take away 7 and 8 is left. Take away 8 and 7 is left.

\(15-7=8\) and \(15-8=7\)

Problem 13: Missing numbers

1. \(9+7=16\), so the missing number is 7.
2. \(5+6=11\), so the missing number is 6.
3. \(8+3=11\), so the missing number is 11.

7, 6, 11

Problem 14: Circle the sixes

\(14-8=6\), \(15-8=7\), \(13-7=6\), \(12-5=7\).

\(14-8\) and \(13-7\)

Problem 15: Mixed differences

1. \(16-8=8\)
2. \(17-10=7\)
3. \(15-9=6\)
4. \(19-4=15\)

8, 7, 6, 15

Grade 1 Subtraction Worksheet Answer Key: problems 16–20

Problem 16: Cubes: how many more?

Match the cubes one to one. Four of Mei’s cubes have no match. Check: \(5+4=9\).

\(9-5=4\), so Mei has 4 more cubes

Problem 17: Grapes

Take away: \(15-6\). Think \(6+9=15\).

\(15-6=9\), so 9 grapes are left

Problem 18: Stickers given away

Ask: 8 plus what makes 14? Count up: 9, 10, 11, 12, 13, 14. That is 6. Check: \(8+6=14\).

\(14-8=6\), so she gave away 6 stickers

Problem 19: Cards: how many fewer?

Find the difference: \(12-7\). Think \(7+5=12\).

\(12-7=5\), so Sofia has 5 fewer cards

Problem 20: Fish in a tank

Subtract the orange fish: \(13-8\). Think \(8+5=13\).

\(13-8=5\), so 5 fish are yellow

Grade 1 Subtraction Worksheet Answer Key: problems 21–22

Problem 21: Crackers

The crackers he ate and the crackers left make the start: \(9+4=13\). Check: \(13-4=9\).

13 crackers

Problem 22: Pencils for friends

First: \(19-6=13\). Next: \(13-5=8\). Check another way: \(6+5=11\) and \(19-11=8\).

8 pencils

How to use this grade 1 subtraction worksheet answer key

Read this grade 1 subtraction worksheet answer key after trying each problem yourself, and redo any problem you missed.

See every chapter on the Grade 1 math page.