Patterns
Addition
Subtraction
100
AB
100
4 + 10
14
100
10 - 5
5
200
XooXooXoo
ABB
200
8 + 5
13
200
18 - 7
11
300
ABC
300
3 + 12
15
300
12 - 6
6
400
++/++/++/
AAB
400
9 + 6
15
400
25 - 9
16
500
XX==XX==XX==
AABB
500
5 + 13
18
500
35 - 16
19