Umgekehrt plus oder minus rechnen

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12 + 15 = 27
27 = 12
        
58 - 33 = 25
25 = 58
12 + 15 = 27
27 - 15 =
        
58 - 33 = 25
25 + 33 =
12 + 15 = 27
- 15 = 12
        
58 - 33 = 25
+ 33 = 58
41 + 48 = 89
89 = 41
        
75 - 43 = 32
32 = 75
41 + 48 = 89
89 - 48 =
        
75 - 43 = 32
32 + 43 =
41 + 48 = 89
- 48 = 41
        
75 - 43 = 32
+ 43 = 75
91 + 8 = 99
99 = 91
        
67 - 23 = 44
44 = 67
91 + 8 = 99
99 - 8 =
        
67 - 23 = 44
23 + 44 =
91 + 8 = 99
- 8 = 91
        
67 - 23 = 44
+ 23 = 67
46 + 22 = 68
68 = 46
        
51 - 31 = 20
20 = 51
46 + 22 = 68
68 - 22 =
        
51 - 31 = 20
20 + 31 =
46 + 22 = 68
- 22 = 46
        
51 - 31 = 20
+ 31 = 51