Đáp án+Giải thích các bước giải:
`a)-3/(12)-1/-4+(-2)/6`
`=-1/4+1/4+(-1/3)`
`=[(-1/4)+1/4]+(-1/3)`
`=0+(-1/3)`
`=-1/3`
`b)-2/4+2/7-5/(28)`
`=(-1/2)+2/7-5/(28)`
`=(-14/28)+8/(28)-5/(28)`
`=-11/28`
`c)4/(12)+3/8-5/(15)`
`=1/3+3/8-1/3`
`=8/(24)+9/(24)-8/(24)`
`=9/(24)`
`=3/8`
`d)2/3+1/3 : 5/9`
`=2/3+1/3 . 9/5`
`=2/3+3/5`
`=10/15+9/(15)`
`=19/15`
`e)1/3-5/4 . 4/(15)`
`=1/3 - 1/3`
`=0`
`f)4/(11)+(-5/13)+7/(11)+(-8/13)`
`=(4/(11)+7/(11))+[(-5/13)+(-8/13)]`
`=11/11+(-13/13)`
`=1+(-1)`
`=0`
`g)1/3+2/3 . 3/4`
`=1/3+1/2`
`=2/6+3/6`
`=5/6`
`h)(3/8+(-1)/4+5/(12)) : 2/3`
`=[9/(24)+(-6/24)+10/24] : 2/3`
`=13/24 . 3/2`
`=13/16`
`i)-2/7+1/5 : 7/(15)`
`=-2/7+1/5 . (15)/7`
`=(-2/7)+3/7`
`=1/7`
`j)(1/5-1/3). 1/4`
`=(3/(15)-5/(15)). 1/4`
`=-2/(15) . 1/4`
`=-1/(30)`
`k)6/7+5/7 : 5 -8/9`
`=6/7 + 5/7 . 1/5 - 8/9`
`=6/7+1/7 - 8/9`
`=7/7-8/9`
`=1-8/9`
`=1/9`
`l)-5/2 : (3/4-1/2)`
`=(-5/2) : (3/4 - 2/4)`
`=(-5/2) : 1/4`
`=(-5/2) . 4`
`=-10`
`n)1/4 + 3/4 . (-1/2+2/3)`
`=1/4 + 3/4. [(-3/6)+4/6]`
`=1/4+3/4 . 1/6`
`=1/4+1/8`
`=2/8+1/8`
`=3/8`
`o)(3/4+(-7)/2).(10/11+2/(22))`
`=(3/4+(-14)/4).(20/22+2/(22))`
`=(-11)/4 . 22/22`
`=(-11/4) . 1`
`=(-11)/4`
`p)(-5/(24) + 0,75+7/(12)) : (-2 1/4)`
`=(-5/(24)+3/4+7/(12)) : -9/4`
`=(-5/(24)+18/24+14/24) : -9/4`
`=27/24 . -4/9`
`=-1/2`
