1)1/6+1/18*3/4=1/6+1/6*1/4=1/6+1/24=4/24+1/24=5/24
2)4 11/48*6/7-1 4/9=203/48*6/7-13/9=29/8-13/9=261/72-104/72=157/72=
=2 13/72
3)(2/3+5/8-11/12)*5 1/3=(16/24+15/24-22/24)*16/3=11/24*16/3=22/9=
=2 4/9
4)15 4/7 - 4 3/8*(10/7-34/35)=15 4/7-35/8*16/35=15 4/7-2 =13 4/7