???
12
Use the above doubles fact to find:
8+9=
17
???
4
???
6
???
16
Use the above doubles fact to find:
4+5=
9
Use the above doubles fact to find:
5+6=
11
Use the above doubles fact to find:
9+10=
19
Use the above doubles fact to find:
10+11=
21
???
8
???
10
Use the above doubles fact to find:
7+8=
15
???
18
Use the above doubles fact to find:
6+7=
13
Use the above doubles fact to find:
3+4=
7
???
20
Use the above doubles fact to find:
1+2=
3
???
2
???
14
Use the above doubles fact to find:
2+3=
5