Пошаговое объяснение:

а)

1) -1,9 * 4² = -1,9 * 16 = -30,4

2) -30,4 : 3,8 = -8

б)

1) -3 1/9 * 7/15 = -28/9 * 7/15 = -196/135

2) -196/135 : 1 1/27 = -196/135 : 28/27 = -196/135 * 27/28 = -7/5 * 1/1 = -7/5 = -1 2/5

в)

1) 10 - 5 2/3 = 9 3/3 - 5 2/3 = 4 1/3

2) 4 1/3 - 8,5 = 4 1/3 - 8 1/2 = 4 2/6 - 8 3/6 = -4 1/6

3) 4 2/9 + 5 5/18 = 4 4/18 + 5 5/18 = 9 9/18 = 9 1/2

4) -4 1/6 : 9 1/2 = -25/6 : 19/2 = -25/6 * 2/19 = -25/3 * 1/19 = -25/57