1
10 + 30 = 40 1 + 3 = 40 2
15 + 30 = 45 1 + 3 = 45 3
45 + 30 = 15 4 + 3 = 15 4
30 + 10 = 20 3 + 1 = 20 5
100 + 7 = 107 107 6
100 + 30 = 130 130 7
156 + 3 = 159 150 +(6+ 3) = 159 8
156 + 20 = 176 100 + (50 +20) = 176
156 +(5+ 2) = 176 9
156 - 3 = 153 150 +(6+ 3) = 153 10
156 - 20 = 136 100 + (50 -20) = 136
156 +(5 - 2) = 136 11
2 + 2+ 2 +2= 8 3 + 3+ 3 = 9 12
100 - 3 = 97 100 - 5 = 95 13
256 + 2 = 258 200 + (6 +2) = 258 14
256 + 20= 276 200 + (50 +20) = 276 15
2x3=6 4 x 5 = 20 16
10 + 30 + 7 = 47 1+3=4 17
10 + 30 + 57 = 97 1 + 3 + 5= 9 18