解:56-13+39等于( 82 ) ∵已知需求出56-13+39等于多少 ∴56 - 13 + 39 = (60 - 4)- (10 + 3)+(40 - 1) = 60 - 4 - 10 - 3 + 40 - 1 = (60 - 10 + 40)+(-4 - 3 - 1) = (50 + 40)+(-7 - 1) = 90 - 8 = 82 答:56-13+39等于82