1. 1,25+5/6=1¹/₄+5/6=5/4+5/6=(5*3+5*2)/12=(15+10)/12=25/12.
2. (25/12):8¹/₃=(25/12):(25/3)=25*3/(25*12)=1/4.
3. 1/12+1/15-0,05=1/12+1/15-1/20=(1*5+1*4-1*3)/60=(5+4-3)/60=6/60=1/10.
4. (1/10):0,2=(1/10):(2/10)=1/2.
5. (1/4)/(1/2)=1*2/(1*4)=2/4=1/2.
6. 1/2-3/7=(1*7-3*2)/14=(7-6)/14=1/14.
7. (1/14)*4,2=(1/14)*(4¹/₅)=(1/14)*(21/5)=1*21/(14*5)=3/10=0,3.