Calculeaza si verifica dupa model

12 + 79 = 91
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79 + 12 = 91
91 - 12 = 79
91 - 79 = 12
96 - 38 = 58
--------------------
96 - 58 = 38
38 + 58 = 96
58 + 38 = 96
78 - 27 = 51
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78 - 51 = 27
27 + 51 = 78
51 + 27 = 78