Đáp án+Giải thích các bước giải:
`a)3/5+4/15=9/15+4/15=13/15`$\\$`b)(-3)/5+5/7=-21/35+25/35=4/35`
`c)5/6:(-7)/12=5/6.(-12)/7=-10/7`$\\$`d)(-21)/24:(-14)/8=(-21)/24.(-8)/14=1/2`
`e)5/12-(-7)/6=5/12+14/12=19/12`$\\$`f)(-15)/16. 8/(-25)=3/10`
`g)3/5-(-7)/10-13/(-20)=12/20+14/20+13/20=39/20`$\\$`h)1/2+1/(-3)+1/4-(-1)/6=6/12-4/12+3/12+2/12=7/12`