additon
subtract
100

What's 70+9

79

100

90-10

80

200

Whats 80+14

94

200

12-7

5

300

What's 50+10

60

300

10-3

7

400

80+4

84

400

20-10

10

500

90+10

100 that's a pretty big number

500

13-10

3