1+1=
2
2+2=
4
3+3=
6
4+4=
8
5+5=
10
6+6=
12
7+7=
14
8+8=
16
9+9=
18
10+10=
20
20 is double of
10
18 is double of
9
16 is double of
8
14 is double of
7
12 is double of
6
10 is double of
5
8 is double of
4
6 is double of
3
4 is double of
2
2 is double of
1
1+9=
10
2+8=
10
3+7=
10
4+6=
10