Addition Within 20 (Number Lines) — Answer Key
Part A: Trace the Words
Trace each word carefully by following the dotted lines.
1. sum
2. add
3. plus
4. total
5. more
6. equal
Part B: Fill in the Blank
Write the missing word or number on each line.
1. 7 + 8 = 15
Start at 7 on the number line and hop forward 8 spaces to land on 15.
2. 9 + 6 = 15
From 9, count up 6 more: 10, 11, 12, 13, 14, 15. You reach 15.
3. 5 + 7 = 12
Start at 5 and jump 7 spaces forward on the number line to arrive at 12.
4. 8 + 8 = 16
When you add 8 + 8, you are making a double. Two groups of 8 make 16.
Part C: True or False?
Read each statement. Circle True or False.
1. 6 + 5 = 11
True False
True. Count up 5 from 6 on the number line: 7, 8, 9, 10, 11. You land on 11, so the equation is right.
2. 7 + 7 = 15
True False
False. 7 + 7 is a double that equals 14, not 15.
3. 9 + 9 = 18
True False
True. 9 + 9 is a double that equals 18, so this equation is correct.