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\(a,\dfrac{1}{2}-\dfrac{1}{3}-\left(-\dfrac{5}{4}\right)=\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{5}{4}=\dfrac{1\times6-1\times4+5\times3}{12}=\dfrac{6-4+15}{12}=\dfrac{17}{12}\\ b,\dfrac{5}{4}-\dfrac{1}{2}-\dfrac{7}{8}=\dfrac{5\times2-1\times4-7}{8}=\dfrac{10-4-7}{8}=-\dfrac{1}{8}\\ c,\dfrac{1}{5}-\dfrac{1}{2}+\dfrac{9}{10}=\dfrac{1\times2-1\times5+9}{10}=\dfrac{2-5+9}{10}=\dfrac{6}{10}=\dfrac{3}{5}\\ d,\dfrac{5}{4}-\dfrac{1}{3}+\dfrac{7}{6}=\dfrac{5\times3-1\times4+7\times2}{12}=\dfrac{15-4+14}{12}=\dfrac{25}{12}\)
`1/2+(-1/3)-(-5/4)`
`=1/2-1/3+5/4`
`=3/6-2/6+5/4`
`=1/6+5/4`
`=2/12+15/12`
`=17/12`
__
`5/4-1/2+(-7/8)`
`=5/4-1/2-7/8`
`=10/8-4/8-7/8`
`=6/8-7/8`
`=-1/8`
__
`1/5-1/2+9/10`
`=2/10-5/10+9/10`
`=-3/10+9/10`
`=6/10`
`=3/5`
__
`5/4-1/3+7/6`
`=15/12-4/12+14/12`
`=11/12+14/12`
`=25/12`
`#lv`
A= -5/1/7+32/5=0.22857142857142286
B= -2/1/3-1/2/7=119047619047619
\(\left(6-\frac{2}{3}+\frac{1}{2}\right)-\left(5+\frac{5}{3}-\frac{3}{2}\right)-\left(3-\frac{7}{3}+\frac{5}{2}\right)\)
\(=6-\frac{2}{3}+\frac{1}{2}-5-\frac{5}{3}+\frac{3}{2}-3+\frac{7}{3}-\frac{5}{2}\)
\(=\left(6-5-3\right)+\left(-\frac{2}{3}-\frac{5}{3}+\frac{7}{3}\right)+\left(\frac{1}{2}+\frac{3}{2}-\frac{5}{2}\right)\)
\(=-2+0-\frac{1}{2}\)
\(=-\frac{4}{2}-\frac{1}{2}\)
\(=-\frac{5}{2}\)
a) 18.17 - 3.6.7
= 18.17-18.7
=18.( 17 - 7 )
= 18 . 10
= 180
b) 54 - 6.( 17 + 9)
= 6.9 - 6 . 26
= 6.( 9 - 26 )
= 6 . ( - 17 )
= -102
c) 33.(17 - 5 ) - 17.(33-5)
= 33.17 - 33 .3 - 17.33 - 17 . 5
= 33.17 + ( -33 ) .3 + ( - 17) .33 + ( -17) .5
= 33.17 + ( - 17) . 33 + 33 . ( - 3) + ( -17 ) .5
= 33. [ 17 + ( -17 ) + ( - 3 )] + (-17) . 5
= 33 . ( - 3 ) + ( -17 ) .5
= -99 + ( - 85)
= -184
a) 18 . 17 - 3 . 6 . 7 b) 54 - 6 . ( 17 + 9 )
= 306 - 126 = 48 . 26
= 180 = 1248
,mk giúp đc từng đó nha
\(A=\left(6-\frac{2}{3}+\frac{1}{2}\right)-\left(5+\frac{5}{3}-\frac{3}{2}\right)-\left(3-\frac{7}{3}+\frac{5}{2}\right)\)
\(=6-\frac{2}{3}+\frac{1}{2}-5-\frac{5}{3}+\frac{3}{2}-3+\frac{7}{3}-\frac{5}{2}\)
\(=6-5-3+\left(\frac{-2}{3}+\frac{-5}{3}+\frac{7}{3}\right)+\left(\frac{1}{2}+\frac{3}{2}-\frac{5}{2}\right)\)
\(=-2+0+\frac{-1}{2}=\frac{-5}{2}\)
Thank you!