Fact Families (Addition & Subtraction to 20) — Answer Key
Part A: Trace the Words
Trace each word carefully by following the dotted lines.
1. family
2. fact
3. add
4. minus
5. sum
6. parts
Part B: Fill in the Blank
Write the missing word or number on each line.
1. 3 + 5 = 8
Start at 3 and count up 5 more (4, 5, 6, 7, 8) to land on 8. This is the first equation in the 3, 5, 8 fact family.
2. 5 + 3 = 8
Switching the parts still gives the same whole, so 5 + 3 equals 8 just like 3 + 5. This rule is called the turn-around fact.
3. 8 - 3 = 5
Start with the whole 8 and take away 3, leaving the other part, 5. Subtraction undoes the addition fact 3 + 5 = 8.
4. 8 - 5 = 3
Take 5 away from 8 and you are left with 3, the other part of the family. The numbers 3, 5, and 8 always work together in four facts.
Part C: True or False?
Read each statement. Circle True or False.
1. 4 + 7 = 11 is in the same fact family as 11 - 7 = 4.
True False
True, because both equations use the very same numbers 4, 7, and 11. Taking 7 away from 11 leaves 4, which matches the addition fact.
2. 6 + 3 = 9 is in the same fact family as 9 - 2 = 7.
True False
False, because the second equation uses 2 and 7, not the 6 and 3 from the first. A real fact family shares all three numbers across every equation.
3. 5 + 9 = 14 is in the same fact family as 14 - 9 = 5.
True False
True, because the trio 5, 9, and 14 appears in both equations. Subtraction simply undoes the addition, returning the other part.