17/5:100%*40%=1 9/25
------------------------------
2*3*4/3*5=2*4/5=8/5
3*3*2*2/3*2*5*2=3/5
7*2*4/3*3*2*4=7/9
3*2*7/11*2*3=7/11
3*3*2*3/3*3*3*3=2/3
2*3*2*7/5*2*3*3=14/15
1/7 - 2,5 = 1/7 - 25/10 = 1/7 - 5/2 = 2/14 - 35/14 = - 33/14 = - 2целых 5/14
-------------------------------------------------------
1 1/2 - 0,5 = 3/2 - 5/10 = 3/2 - 1/5 = 15/10 - 2/10 = 13/10 = 1целая 3/10