Fact Families: Addition & Subtraction — Answer Key
Part A: Complete the Fact Family
Write the missing number to complete each equation.
1. 5 + 9 = 14
In the fact family for 5, 9, and 14, 5 + 9 = 14.
2. 9 + 5 = 14
In the fact family for 5, 9, and 14, addition can be done in either order: 9 + 5 = 14.
3. 14 - 5 = 9
In the fact family for 5, 9, and 14, subtraction is the inverse of addition: 14 - 5 = 9.
4. 14 - 9 = 5
In the fact family for 5, 9, and 14, 14 - 9 = 5.
5. 7 + 8 = 15
In the fact family for 7, 8, and 15, 7 + 8 = 15.
6. 8 + 7 = 15
In the fact family for 7, 8, and 15, addition can be done in either order: 8 + 7 = 15.
7. 15 - 7 = 8
In the fact family for 7, 8, and 15, subtraction is the inverse of addition: 15 - 7 = 8.
8. 15 - 8 = 7
In the fact family for 7, 8, and 15, 15 - 8 = 7.
9. If 6 + 8 = 14, then 14 - 6 = 8.
Since 6 + 8 = 14, subtracting 6 from 14 gives back 8: 14 - 6 = 8.
Part B: Match the Fact Family Partners
Draw a line from each addition fact to its subtraction partner.
1. Match each addition fact to its subtraction partner.
4 + 9 = 13
→ 13 - 9 = 4
12 - 5 = 7
6 + 8 = 14
→ 14 - 8 = 6
13 - 9 = 4
7 + 5 = 12
→ 12 - 5 = 7
12 - 9 = 3
3 + 9 = 12
→ 12 - 9 = 3
14 - 8 = 6
4 + 9 = 13 pairs with 13 - 9 = 4 (fact family 4, 9, 13). 6 + 8 = 14 pairs with 14 - 8 = 6 (fact family 6, 8, 14). 7 + 5 = 12 pairs with 12 - 5 = 7 (fact family 5, 7, 12). 3 + 9 = 12 pairs with 12 - 9 = 3 (fact family 3, 9, 12).