Răspuns:
Explicație pas cu pas:
( 3 + 2 + 4 ) × 10 = 9 × 10 = 90 → primul mod
3 × 10 + 2 × 10 + 4 × 10 = 30 + 20 + 40 = 90 → al doilea mod
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( 5 + 1 + 2 ) × 9 = 8 × 9 = 72 → primul mod
5 × 9 + 1 × 9 + 2 × 9 = 45 + 9 + 18 = 54 + 18 = 72 → al doilea mod
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8 × ( 7 - 3 ) = 8 × 4 = 32 → primul mod
8 × 7 - 8 × 3 = 56 - 24 = 32 → al II-lea mod ( aplic distributivitatea inmultirii fata de diferenta data)
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10 × ( 4 + 3 - 2 ) = 10 × ( 7 - 2 ) = 10 × 5 = 50 → primul mod
10 × 4 + 10 × 3 - 10 × 2 = 40 + 30 - 20 = 70 - 20 = 50 → al II-lea mod
