здравствуй.
(17 + 8) + 20 = 50 (17 + 8) + 25 = 50
25 + 20 = 50 25 + 25 = 50
45 ≠ 50 50 = 50
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(100 - 29) - 6 = 65
71 - 6 = 65
65 = 65
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31 + 60 - 3 = 81 31 + 60 - 10 = 81
91 - 3 = 81 91 - 10 = 81
88 ≠ 81 81 = 81
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(46 + 4) - 40 = 10
50 - 40 = 10
10 = 10
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удачи в учёбе.