Bài `1` nhỉ?
`1a,5/14-7/2=5/14-49/14=-22/7`
`b,9/20-1/12=11/30`
`c,3/8-(3/4-1/2)=3/8-1/4=1/8`
`d,-2/3+3/4-1/2+1/6=-5/12+1/6=-1/4`
`e,-7/12-3/36=-2/3`
`f,1/4-1/6+1/12=1/12+1/12=1/6`
`g,1/10--1/12+1/15=11/60+1/15=1/4`
`h,27/23--5/21-4/23+16/21+1/2=26/21+16/21+1/2=5/2`