a) 15/3 - 2/3 = 13/3

b) 15/20 = 3/4

c) 1/24

d) 2/5 - 1/5 = 1/5

a, = 17/3

b, = 3/4

c, = 1/24

d, = 6/15 - 1/5 = 1/5

a, \(\dfrac{5}{1}+\dfrac{2}{3}=\dfrac{15}{3}+\dfrac{2}{3}=\dfrac{17}{3}\)

b, \(3\times\dfrac{1}{4}=\dfrac{3}{1}\times\dfrac{1}{4}=\dfrac{3}{4}\)

c, \(\dfrac{3}{8}-\dfrac{1}{3}=\dfrac{9}{24}-\dfrac{8}{24}=\dfrac{1}{24}\)

d, \(\dfrac{6}{15}-\left(\dfrac{1}{3}:\dfrac{5}{3}\right)=\dfrac{6}{15}-\left(\dfrac{1}{3}\times\dfrac{3}{5}\right)=\dfrac{6}{15}-\dfrac{3}{15}=\dfrac{3}{15}=\dfrac{1}{5}\)

`3/5:(-1/15-1/6)+3/5:(-1/3-1 1/15)`

`=3/5:[-7]/30+3/5:[-7]/5`

`=3/5 . [-30]/7+3/5 . [-5]/7`

`=3/5 .([-30]/7+[-5]/7)`

`=3/5 . [-5]=-3`

\(\dfrac{3}{5}:\left(-\dfrac{1}{15}-\dfrac{1}{6}\right)+\dfrac{3}{5}:\left(-\dfrac{1}{3}-1\dfrac{1}{15}\right)\)

\(=\dfrac{3}{5}:\left(-\dfrac{6}{90}-\dfrac{15}{90}\right)+\dfrac{3}{5}:\left(-\dfrac{1}{3}-\dfrac{16}{15}\right)\)

\(=\dfrac{3}{5}:\dfrac{-7}{30}+\dfrac{3}{5}:\left(-\dfrac{5}{15}-\dfrac{16}{15}\right)\)

\(=\dfrac{3}{5}:\dfrac{-7}{30}+\dfrac{3}{5}:\dfrac{-7}{5}\)

\(=\dfrac{3}{5}\times\dfrac{-30}{7}+\dfrac{3}{5}\times\dfrac{-5}{7}\)

\(=\dfrac{3}{5}\times\left(\dfrac{-30}{7}+\dfrac{-5}{7}\right)\)

\(=\dfrac{3}{5}\times\left(-5\right)\)

\(=-3\)

a) \(=\dfrac{157}{8}.\dfrac{12}{7}-\dfrac{61}{4}.\dfrac{12}{7}=\dfrac{12}{7}\left(\dfrac{157}{8}-\dfrac{61}{4}\right)=\dfrac{12}{7}.\dfrac{35}{8}=\dfrac{15}{2}\)

b) \(\dfrac{2}{5}.\dfrac{1}{3}-\dfrac{2}{15}\div\dfrac{1}{5}+\dfrac{3}{5}.\dfrac{1}{3}=\dfrac{1}{3}\left(\dfrac{2}{5}+\dfrac{3}{5}\right)-\dfrac{2}{15}.5=\dfrac{1}{3}.1-\dfrac{2}{3}=\dfrac{1}{3}-\dfrac{2}{3}=-\dfrac{1}{3}\)

c) \(=-\dfrac{80}{9}\)

d) \(=-\dfrac{1}{6}\)

a.=\(\dfrac{157}{8}:\dfrac{7}{12}-\dfrac{61}{4}:\dfrac{7}{12}=\dfrac{471}{14}-\dfrac{183}{7}=\dfrac{15}{2}\)

b.=\(\dfrac{2}{15}-\dfrac{2}{3}+\dfrac{1}{5}=-\dfrac{1}{3}\)

c.\(\left(\dfrac{10}{3}+2.5\right):\left(\dfrac{19}{6}-\dfrac{21}{5}\right)-\dfrac{11}{31}=\dfrac{35}{6}:\left(-\dfrac{31}{30}\right)-\dfrac{11}{31}=-\dfrac{175}{31}-\dfrac{11}{31}=-6\)

d.\(\left[6+\dfrac{1}{8}-\dfrac{1}{2}\right]:\dfrac{3}{12}=\dfrac{45}{8}:\dfrac{3}{12}=\dfrac{45}{2}\)

a) \(=\dfrac{1}{3}+\dfrac{1}{4}.4-\dfrac{1}{2}=\dfrac{4}{3}-\dfrac{1}{2}=\dfrac{8}{6}-\dfrac{3}{6}=\dfrac{5}{6}\)

a)1/3+25%.4-1/2

= 1/3+1/4.4-1/2

=1/3+1-1/2

=5/6

b)5/7.1/15+5/7-5/7.3/15

=5/7.(1/15-3/15)+5/7

=5/7.(-2/15)+5/7

=-2/21+5/7

=13/21

a,=1/3+1/4.4-1/2

=1/3+1-1/2

=4/3-1/2

=5/6

-2/15

-4/35

-5/3

10

-8/3

-7/2

-9

-4/3

Chúc em học giỏi

\(=\dfrac{-2}{15}\\ =\dfrac{-4}{35}\\ =-1\\ =10\\ =\dfrac{-8}{3}\\ =-7\\ =-9\\ =\dfrac{-4}{3}\)

-2/15

-4/35

-5/3

10

-8/3

-7/2

-9

-4/3

Chắc ko

nhìn thấy nản

Thấy mà hết muốn làm

\(A=\left(\dfrac{1}{3}+\dfrac{3}{5}+\dfrac{1}{15}\right)-\left(\dfrac{3}{4}+\dfrac{2}{9}+\dfrac{1}{36}\right)+\dfrac{1}{64}\)

\(=\dfrac{5+9+1}{15}-\dfrac{27+8+1}{36}+\dfrac{1}{64}\)

=1/64

a) \(\dfrac{21}{15}\) + \(\dfrac{2}{5}\) = \(\dfrac{9}{5}\)
b)  \(\dfrac{6}{16}\) + \(\dfrac{1}{8}\) = \(\dfrac{1}{2}\)

c)  \(\dfrac{3}{12}\) + \(\dfrac{3}{4}\) = 1