Number Before
Number after
Addition
Subtraction
Multiplication
100

31

30

100

79

80

100
2+2

4

100

20-3

17

100

2x1

2

200

80

79

200

85

86

200

4+5

9

200
41-6

35

200

3x4

12

300

130

129

300

130

131 

300
9+9

18

300

54-4

50

300

4x5

20

400

145

144

400

140

141

400

13+7

20

400

123-11

112

400

6x3

18

500

231

230

500

221

222

500

20+3

23

500

140-25

115

500

9x6

54