1 7/8*(-1 7/9)-4 2/9*(-3/8)=

(- 3 8/9*3/7-4/27)*3 3/8=

что это?

= (-35/9*3/7 - 4/27) * 27/8 = (-5/3 - 4/27)*27/8 = (-45/27 - 4/27) * 27/8 = -49/27 * 27/8 = -49/8 = -6 1/8

1 7/8 * (-1 7/9) - 4 2/9 * (-3/8) = -1 3/4,

1) 1 7/8 * (-1 7/9) = -15/8 * 16/9 = - 10/3 = - 3 1/3,
2) 4 2/9 * (-3/8) = - 38/9 * 3/8 = - 19/12 = - 1 7/12,
3) -3 1/3 - (-1 7/12) = -10/3 + 19/12 = -40/12 + 19/12 = - 21/12 = - 1 3/4