S/D
S/M
A/M
A/D
Add
100

X/4 - 3 = 25

X =7

100

5x - 5 = 30

X=7

100

5x + 3 = 28

C = 5

100

X/7 + 6 = 55

X = 7

100

X + 12 = 135

X = 123

200

X/5 - 5 = 20

X=5

200

6x - 7 = 35

X = 7

200

9x + 9 = 99

X = 10

200

X/6 + 2 =38

  X = 6

200

X + 18 = 127

X = 109

300

X/7 - 3 = 18

X = 3

300

3x - 6 = 30

X = 12

300

3x + 12 = 45

X = 11

300

X/5 + 12 = 37

X = 5

300

X + 13 = 201

X = 188


400

X/8 - 5 = 35

X = 5

400

5x - 10 = 30

X = 8

400

7x + 13 = 76

X = 9

400

X/4 + 13 = 37

X = 6

400

X + 19 = 325

X = 306

500

X/10 - 10 = 90

X = 10

500

4x - 6 = 30

X = 9

500

8x + 16 = 104

 X = 11

500

X/6 + 12 = 78

X = 11

500

X + 18 = 475

X = 457