a]=[75/270-63/270]:8/3×5/2=12/270×3/8×5/2=21/45×15/16=1/24 b]=27/20:27/20+2=1+2=3 :½:¼=3:2=1,5 c]=2,5:10+10:5/2-2 i ⅙=0,25+10×⅖-13/6=0,25+4-13/6=4,25-13/6=17/4-13/6=51/12-26/12=25/12=2 i 1/12 :3 i 17/36=25/12×36/125=⅗ d]==3+4,2:0,1:[1×10/3-7/3]×5/6=[3+42]×6/5=54 e]=⅓:⅕×3/2×4/3:2 i 6/7=1/3×10/3×4/3×7/20=280/540=28/54=14/27