1) (-2 целых 3/4 - 3/8) x 160 = (-11/4 - 3/8) x 160 = (-22/8 - 3/8) x 160= -25/8 x 160 = -4000/8 = -500
2) (3/4 + 2 целых 3/8) х 25,8 = (6/8 + 19/8) х 25,8 = 25/8 х 25,8 = 25/8 x 25 целых 8/10 = 25/8 x 258/10 = 645/8 = 80 целых 5/8
3) (728(2) - 26(2)) : 754 = (728х728 - 26х26) : 754 = (529984 - 676) : 754 = 529308 : 754 = 702
4) 2/5 + 1/4 + 2 целых = 2/5 + 1/4 + 2/1 = 8/20 + 5/20 + 40/20 = 53/20 = 2 целых 13/20
5) 0,24х10(6)/0,6 х 10(4) = 0,24х(10х10х10х10х10х10)/0,6 х (10х10х10х10) = 4х(10х10) = 4х100 = 400