1.)3 7/12 - 1 7 /20=43/12-27/20=(129-135)/60=-6/60=0.1
2.) 4 2/5 - 3 4/5 =22/5-19/5=3/5
3.) 4 11/16 + 3 11/12= (225+188)/48=413/48=8(целых) 29/48
4.)3 1/6 + 3 5/13 =19/6+44/13=(247+264)/78=511/78=6 43/78
5.)2 2/15 + 2 1/5 = 4 1/5
6. 4 - 3 8/19 =1 8/19
7. 11/21 + 3 10/21 =4
8. 4 3/14 - 1=3 3/14