1.
999+373+(631-456)•2= 1372 + 631×2 - 456×2 = 1372 + 1262 - 912 = 1722
2 способ:
999+373+(631-456)•2= 1372 + 175×2 = 1372 + 350 = 1722
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2.
8653-3314•(34+78)-(91+20):1= 8653 - 3314×112 - 111÷1 = 8653 - 371168 - 111 = -362626
2 способ:
8653-3314•(34+78)-(91+20):1= 8653 - 3314×34 - 3314×78 - 91 - 20 = 8653 - 112676 - 258492 - 111 = -362626
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23 + _ _ = 58
58 - 23 = 35 (второе слагаемое)
23 + 35 = 58