`Đáp án +Giải thích các bước giải:`
a, 2 `2/3`+3 `3/4`=` 8/3+ 15/4`=` 77/12`
b, 2 `3/5` . 7 `5/6`= `13/5 . 47/6`= `611/30`
c, 1 `3/5`-`2/3+1/3`= `8/5-2/3+1/3`=` 3/5-(2/3-1/3)`=`3/5-1/3=4/15`
d, 4 `5/6`:`3/4`×2 `4/5`=`29/6:3/4 . 14/5`=` 812/45`
e, 3 `19/35:5 7/9`=`124/35:52/9`=`279/455`
g, 1 `3/4`+2 `2/8`=`7/4+9/4`=`4`
h, 9 `1/8:2 7/9`=`73/8:25/9`=`657/200`