Đáp án:
Giải thích các bước giải:
a) `5/21+0,5-19/23+16/21-4/23`
`=5/21+1/2-19/23+16/21-4/23`
`=5/21+1/2+(-19)/23+16/21+(-4)/23`
`=(5/21+16/21)+((-19)/23+(-4)/23)+1/2`
`=1-1+1/2`
`=1/2`
b) `(3/4+2/3):17/4-3/4`
`=3/4:17/4+2/3:17/4-3/4`
`=3/17+8/51-3/4`
`=1/3-3/4`
`=(-5)/12`
c)` (-5)^2. 7/45+(-5)^2. 11/45`
`=25*7/45+25*11/45`
`=25.(7/45+11/45)`
`=25.6/15`
`=10`
d) `5 1/3+2,5.(1/3-5/12)`
`=16/3+5/2*(-1)/12`
`=16/3+(-5)/24`
`=41/8`
e) `(1/2-2/3)-(5/3-3/2)+(7/3-5/2)`
`=1/2-2/3-5/3+3/2+7/3-5/2`
`=1/2+(-2)/3+(-5)/3+3/2+7/3+5/2`
`=(1/2+3/2-5/2)+((-2)/3+(-5)/3+7/3)`
`=(-1)/2+0`
`=(-1)/2`
