Word Problems: Add & Subtract Within 20 — Answer Key
Part A: Solve the Word Problems
Read each problem. Use the box to show your work. Write the answer.
1. Ella has 8 markers. Her friend gives her 5 more. How many markers does Ella have now?
Answer: 13 markers
8 + 5 = 13. Ella starts with 8 markers and gets 5 more, so she has 13 markers in all.
2. There are 14 children at the park. Then 6 go home. How many children are still at the park?
Answer: 8 children
14 - 6 = 8. There were 14 children, then 6 left, leaving 8 children still at the park.
3. A box has 7 red balls and 5 blue balls. How many balls are in the box in all?
Answer: 12 balls
7 + 5 = 12. Putting the red and blue balls together gives 7 + 5 = 12 balls in the box.
Part B: Key Words
Fill in the blank with 'add' or 'subtract'.
1. When you see 'in all,' you should add.
The phrase 'in all' means joining groups together, which is what addition does, so you add.
2. When you see 'how many are left,' you should subtract.
'How many are left' tells you something is being taken away, and subtraction is how you find what remains.
3. When you see 'how many more,' you should subtract.
Comparing two amounts to see the difference uses subtraction, so 'how many more' means you subtract.
4. When you see 'altogether,' you should add.
'Altogether' means combining everything into one total, so you add to find the whole.
5. When you see 'take away,' you should subtract.
When you 'take away,' part of a group is removed, and subtraction is the operation that does that.