1)вычислите -21-(41-85) 2) (7/9-5/6)*3/5 в дробях 3)вычислите 45-7,2: 18

1) -21-(41-85) = -21 - (-44) = -21 + 44 = 23

2) (7/9 - 5/6) * 3/5 = 7/9 * 3/5 - 5/6 * 3/5 = 7/15 - 1/2 = 14/30 - 15/30 = -1/30

3) 45 - 7,2/18 = 45 - 72/180 = 45 - 4/10 = 45 - 0,4 = 44,6