Ответ:

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

2)429.8 : (140)=3.07

3)3:49/200=0.735

4)-3 5/8 - 3.07 = - 3.625-3.070=-6.695

5)-6.695 - 0.735= - 7.43