câu 5 : tính
a/`-9/34.`17/4`=`-9/2`.`1/4`=`-9/8`
b/`-20/41`.`-4/5`=`-4/41`.`-4/1=`16/41`
c/`-5/2`:`3/4`=`-5/2`.`4/3`=`-5/1`.`2/3`=`-10/3`
d/4`1/5`:(-2`4/5`)=`21/5`:(`-14/5`)=`21/5`.(`5/-14`)=`-3/1`.(`1/2`)=`-3/2`=-1`1/2`
e/1,8:(`-3/4`)=`18/10`:(`-3/4`)=`9/5`:(`-3/4`)=`9/5`.(`4/-3`)=`-3/5`.`4/1`=`-12/5`
g/20%+`-2/5`.`1/2`=`2/10`+`-2/5`.`1/2`=`1/5`+`-2/5`.`1/2`=`1/5`+`-2/10`=`1/5`+`-1/5`=0
