(2/15+7/12)*30/40-2:2 2/1*5/32
1. 2/15+7/12=(8+35)/60=43/60
43/60*30/40=43/80
2:2 2/1=2/1:4/1=2/1*1/4=1/2
1/2*5/32=5/64
43/80-5/64=(344-50)/640=294/640=147/320
В 1 примере -0.46 Во 2 примере 0.31