59/7-4.125-15/8
=59/7-4.125-1.875
=59/7-(4.125+1.875)
=59/7-6
=59/7-42/7
=17/7
20-8.35X3/5-1.65X0.6
=20-8.35×0.6-1.65×0.6
=20-0.6*(8.35+1.65)
=20-0.6*10
=20-6=14