The document provides an example method for adding two neighboring numbers on a number line. The method is to double the lower number and add one to the sum. It then applies this method to solve several addition problems as examples and lists the answers to check work.

3. 5 + 5=10 5 + 5 = 10 9 + 9 = 18
10 + 1 = 11 + 1 = 11
10 18 + 1 = 19
3 + 3= 6
1+1=2
6+1=7
2+1=3
8 + 8 = 16
16 + 1 = 17 7 + 7 = 14
14 + 1 = 15
2+2=4
4+1=5

4. Remember if you have two neighbors on the number line,
DOUBLE the LOWER number and add ONE to the SUM 
7+8=? 5+6=? 4+3=?
9+8=? 2+3=? 5+4=?
10 + 9 = ? 1+2=?

5. Check your work below:
7 + 8 = 15 5 + 6 = 11 4+3=7
9 + 8 = 17 2+3=7 5+4=9
10 + 9 = 19 1+2=3