Addition
2+2
4
1
5 tens and 3 ones
53
3 tens 0 ones
30
12+1
13
5+2
7
2-1
1
2 tens 0 ones
20
5 tens 2 ones
52
9 tens 4 ones
94
6+3
9
2-0
2
6 tens 6 ones
66
7 tens 8 ones
78
15-9
6
10+0
10
8-5
3
4 tens 3 ones
43
6 tens 0 ones
60
19-19
0
12+6
18
10-8
2
1 tens 4 ones
14
9 tens 3 ones
93
15+_=20
5