Răspuns :
Salut!
Calculeaza în doua moduri :
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❶ 6 × ( 21 + 44 ) = 6 × 65 = 390
❷ 6 × 21 + 6 × 44 = 126 + 264 = 390
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❶ ( 53 + 73 ) × 3 = 126 × 3 = 378
❷ 53 × 3 + 73 × 3 = 159 + 219 = 378
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❶ 10 × ( 11 + 66 ) = 10 × 77 = 770
❷ 10 × 11 + 10 × 66 = 110 + 660 = 770
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Bafta! =)