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. Ms. Clark has 9 pencils on her desk. She gives 5 to students. How many pencils does she have left?
Answer: 4 pencils
9 - 5 = 4. Ms. Clark started with 9 pencils and gave 5 away, leaving 4 pencils on her desk.
2. Jake sees 6 ducks on the pond. Then 7 more ducks swim over. How many ducks are on the pond now?
Answer: 13 ducks
6 + 7 = 13. Jake had 6 ducks, and 7 more swam over, making 13 ducks on the pond now.
3. There are 15 books on the shelf. A student takes 8 books. How many books are still on the shelf?
Answer: 7 books
15 - 8 = 7. Taking 8 books from the 15 on the shelf leaves 7 books still there.
Part B: Choose the Operation
Write 'add' or 'subtract' to tell what you would do to solve each problem.
1. Tom has 12 grapes. He eats 4. To find how many are left, you subtract.
Eating grapes takes them away from the group, so to find what's left you subtract: 12 - 4 = 8.
2. Ana has 6 flowers. She picks 8 more. To find the total, you add.
Picking more flowers joins them with the ones Ana already has, so you add: 6 + 8 = 14.
3. There are 11 cars. Then 3 drive away. To find how many are left, you subtract.
Cars driving away means fewer are left, so subtraction is the right operation: 11 - 3 = 8.
4. Rosa has 5 stickers. Kai gives her 9 more. To find the total, you add.
Getting more stickers makes the total grow, so you add Rosa's 5 and Kai's 9 to find the total.
5. A dog has 13 treats. He eats 7. To find how many are left, you subtract.
Treats being eaten are taken away from the dog's pile, so you subtract: 13 - 7 = 6.