Subtraction Within 20 — Answer Key
Part A: Multiple Choice
Circle the correct answer for each question.
1. What is 18 - 9?
A) 7
B) 8
C) 9
D) 10
C is correct because 18 - 9 = 9.
2. Mia had 15 stickers. She gave away 7. How many does she have left?
A) 6
B) 7
C) 8
D) 9
C is correct because 15 - 7 = 8, so Mia has 8 stickers left.
3. Which subtraction fact belongs to the same family as 9 + 4 = 13?
A) 13 - 4 = 9
B) 13 - 5 = 8
C) 13 - 3 = 10
D) 13 - 6 = 7
A is correct because 13 - 4 = 9 is the related subtraction fact in the same fact family as 9 + 4 = 13.
4. What number makes this true? 20 - ___ = 11
A) 7
B) 8
C) 9
D) 10
C is correct because 20 - 9 = 11.
Part B: Fill in the Missing Number
Write the missing number to complete each number sentence.
1. 17 - 8 = 9
Since 17 - ___ = 9, the missing number is 17 - 9 = 8.
2. 14 - 6 = 8
Since ___ - 6 = 8, the missing number is 6 + 8 = 14.
3. 19 - 8 = 11
Since 19 - ___ = 11, the missing number is 19 - 11 = 8.
4. 13 - 7 = 6
Since ___ - 7 = 6, the missing number is 7 + 6 = 13.
5. 20 - 6 = 14
Since 20 - ___ = 14, the missing number is 20 - 14 = 6.