This grade 1 addition worksheet answer key solves all 22 problems of the addition within 20 worksheet step by step.
Here are the full worked answers for the Grade 1 addition worksheet. Each answer shows the strategy: counting on, making a ten, or using a double. Read each step with the child, then let the child try a similar problem alone.
Grade 1 Addition Worksheet Answer Key: problems 1–5
Problem 1: Count and add
Count the blue ones: 5. Count the orange ones: 3. Put them together: \(5+3=8\).
\(5+3=8\)
Problem 2: Ten frame sentence
There are 4 blue counters and 3 orange counters. \(4+3=7\).
\(4+3=7\)
Problem 3: Find the sums
- \(6+2=8\)
- \(7+3=10\)
- \(9+0=9\). Adding 0 changes nothing.
- \(4+5=9\)
8, 10, 9, 9
Problem 4: Small doubles
- \(2+2=4\)
- \(3+3=6\)
- \(4+4=8\)
- \(5+5=10\)
4, 6, 8, 10
Problem 5: Count on with a number line
Hop one step at a time: 6, 7, 8, 9. You land on 9.
\(5+4=9\)
Grade 1 Addition Worksheet Answer Key: problems 6–10
Problem 6: Count on from the bigger number
The bigger number is 8. Start at 8 and count on 3: 9, 10, 11.
\(3+8=11\)
Problem 7: Show a double
Each frame shows 6. Six plus six is a double.
\(6+6=12\)
Problem 8: Near doubles
- \(7+7=14\), and one more is 15. \(7+8=15\).
- \(6+6=12\), and one more is 13. \(6+7=13\).
15 and 13
Problem 9: Make a ten with frames
The first frame needs 1 more. Move 1 orange counter. Now the first frame has 10 and the second has 3. \(10+3=13\).
\(9+4=13\)
Problem 10: Make a ten with numbers
Split 6 into 2 and 4. \(8+2=10\). Then \(10+4=14\).
4, 4, 14
Grade 1 Addition Worksheet Answer Key: problems 11–15
Problem 11: Switch the order
Switch 3 and 9. The sum stays the same.
\(9+3=12\)
Problem 12: Circle the twelves
\(6+6=12\), \(7+4=11\), \(8+4=12\), \(9+2=11\).
\(6+6\) and \(8+4\)
Problem 13: Three numbers
Find two numbers that make 10: \(7+3=10\). Then add 2: \(10+2=12\).
12
Problem 14: Three numbers again
\(4+6=10\). Then \(10+5=15\).
15
Problem 15: Two sentences
The parts are 8 and 5. The sum is 13. Switch the parts for the second sentence.
\(8+5=13\) and \(5+8=13\)
Grade 1 Addition Worksheet Answer Key: problems 16–20
Problem 16: Mixed sums
- \(9+9=18\)
- \(10+7=17\)
- \(8+8=16\), and one more is 17. \(8+9=17\)
- \(7+7=14\)
18, 17, 17, 14
Problem 17: Cookies at the bake sale
Add the parts: \(8+5\). Make a ten: \(8+2=10\), then \(10+3=13\).
13 cookies
Problem 18: Balloons
Think of the double \(6+6=12\). Seven is one more than 6, so add 1: 13.
13 balloons
Problem 19: Missing stickers
Think: 9 plus what number makes 14? Count on from 9: 10, 11, 12, 13, 14. That is 5 counts. Check: \(9+5=14\).
5 stickers
Problem 20: Zoo animals
Add 4 and 6 first because they make 10: \(4+6=10\). Then \(10+5=15\).
15 animals
Grade 1 Addition Worksheet Answer Key: problems 21–22
Problem 21: Ducks in the pond
Think: what number plus 6 makes 13? Try 7: \(7+6=13\). It works.
7 ducks
Problem 22: Pages read this week
\(6+7=13\). Then \(13+5=18\). Check by another order: \(5+7=12\), and \(12+6=18\).
18 pages
How to use this grade 1 addition worksheet answer key
Read this grade 1 addition worksheet answer key after trying each problem yourself, and redo any problem you missed.
See every chapter on the Grade 1 math page.
