Question

TÍNH BẰNG CÁCH THUẬN TIỆN NHẤT

A)\(\frac{2}{3}\cdot\frac{4}{5}+\frac{1}{3}\cdot\frac{4}{5}=\)

B)\(\frac{1}{2}:\frac{3}{4}+\frac{1}{6}:\frac{3}{4}=\)

C)\(\frac{2}{3}\cdot\frac{4}{5}-\frac{1}{3}\cdot\frac{4}{5}=\)

D)\(\frac{1}{2}:\frac{3}{4}-\frac{1}{6}:\frac{3}{4}=\)

Answer 1

\(\frac{2}{3}.\frac{4}{5}+\frac{1}{3}.\frac{4}{5}=\frac{4}{5}\left(\frac{2}{3}+\frac{1}{3}\right)=\frac{4}{5}.\frac{3}{3}=\frac{4}{5}.1=\frac{4}{5}\)

\(\frac{1}{2}:\frac{3}{4}+\frac{1}{6}:\frac{3}{4}=\frac{3}{4}:\left(\frac{1}{2}+\frac{1}{6}\right)=\frac{3}{4}:\frac{2}{3}=\frac{9}{8}\)

\(\frac{2}{3}.\frac{4}{5}-\frac{1}{3}.\frac{4}{5}=\frac{4}{5}\left(\frac{2}{3}-\frac{1}{3}\right)=\frac{4}{5}.\frac{1}{3}=\frac{4}{15}\)

\(\frac{1}{2}:\frac{3}{4}-\frac{1}{6}:\frac{3}{4}=\frac{3}{4}:\left(\frac{1}{2}-\frac{1}{6}\right)=\frac{3}{4}:\frac{1}{3}=\frac{9}{4}\)

Answer 2

\(\frac{2}{3}.\frac{4}{5}+\frac{1}{3}.\frac{4}{5}=\left(\frac{2}{3}+\frac{1}{3}\right).\frac{4}{5}=1.\frac{4}{5}=\frac{4}{5}\)

\(\frac{1}{2}:\frac{3}{4}+\frac{1}{6}:\frac{3}{4}=\frac{1}{2}.\frac{4}{3}+\frac{1}{6}.\frac{4}{3}=\left(\frac{1}{2}+\frac{1}{6}\right).\frac{4}{3}=\frac{2}{3}.\frac{4}{3}=\frac{8}{9}\)

c,d tương tự 

Answer 3

A) \(\frac{2}{3}\). \(\frac{4}{5}\)+ \(\frac{1}{3}\). \(\frac{4}{5}\)    B) \(\frac{1}{2}\). \(\frac{4}{5}\)+ \(\frac{1}{6}\): \(\frac{3}{4}\)      C) \(\frac{2}{3}\). \(\frac{4}{5}\)- \(\frac{1}{3}\). \(\frac{4}{5}\)         

= \(\left(\frac{2+1}{3}\right)\). \(\frac{4}{5}\)                =  \(\frac{2}{5}\)+ \(\frac{2}{9}\)                         = \(\frac{2}{3}\)- \(\frac{1}{3}\). \(\left(\frac{4-4}{5}\right)\)

= 1 . \(\frac{4}{5}\)                                   = \(\frac{28}{45}\)                                   = \(\frac{1}{3}\). 0

= \(\frac{4}{5}\)                                                                                         = 0

Answer 4

D) 1/2 : 3/4 - 1/6 : 3/4

    = 1/2 - 1/6 : 3/4 - 3/4

    = 3 : 0

    = 0 

Answer 5

A)\(\frac{2}{3}.\frac{4}{5}+\frac{1}{3}.\frac{4}{5}=\left(\frac{2}{3}+\frac{1}{3}\right).\frac{4}{5}=1.\frac{4}{5}=\frac{4}{5}\)
B)\(\frac{1}{2}:\frac{3}{4}+\frac{1}{6}:\frac{3}{4}=\left(\frac{1}{2}+\frac{1}{6}\right):\frac{3}{4}=\frac{2}{3}:\frac{3}{4}=\frac{8}{9}\)
C)\(\frac{2}{3}.\frac{4}{5}-\frac{1}{3}.\frac{4}{5}=\left(\frac{2}{3}-\frac{1}{3}\right).\frac{4}{5}=\frac{1}{3}.\frac{4}{5}=\frac{4}{15}\)
D)\(\frac{1}{2}:\frac{3}{4}-\frac{1}{6}:\frac{3}{4}=\left(\frac{1}{2}-\frac{1}{6}\right):\frac{3}{4}=\frac{1}{3}:\frac{3}{4}=\frac{4}{9}\)

Answer 6

A=4/5               B=9/8              C=4/15              D9/4