Question

tính bằng cách thuận tiện 
a,\(\dfrac{3}{5}\)x\(\dfrac{8}{27}\)x\(\dfrac{5}{3}\)                                         b,\(\dfrac{7}{19}\)x\(\dfrac{1}{3}\)+\(\dfrac{7}{19}\)x\(\dfrac{2}{3}\)

Answer 1

\(a,=\left(\dfrac{3}{5}.\dfrac{5}{3}\right).\dfrac{8}{27}=1.\dfrac{8}{27}=\dfrac{8}{27}\\ b,=\dfrac{7}{19}.\left(\dfrac{1}{3}+\dfrac{2}{3}\right)=\dfrac{7}{19}.\dfrac{3}{3}=\dfrac{7}{19}.1=\dfrac{7}{19}\)

Answer 2

con a bằng 8/27

con b bằng 7/19

Answer 3

\(a.\dfrac{3}{5}\times\dfrac{8}{27}\times\dfrac{5}{3}=\left(\dfrac{3}{5}\times\dfrac{5}{3}\right)\times\dfrac{8}{27}=\dfrac{8}{27}\)

\(b.\dfrac{7}{19}\times\dfrac{1}{3}+\dfrac{7}{19}\times\dfrac{2}{3}=\dfrac{7}{19}\times\left(\dfrac{1}{3}+\dfrac{2}{3}\right)=\dfrac{7}{19}\times1=\dfrac{7}{19}\)

Answer 4

\(a,\dfrac{3}{5}\times\dfrac{8}{27}\times\dfrac{5}{3}\)

\(=\left(\dfrac{3}{5}\times\dfrac{5}{3}\right)\times\dfrac{8}{27}=\dfrac{15}{15}\times\dfrac{8}{27}=1\times\dfrac{8}{27}=\dfrac{8}{27}\)

\(b,\dfrac{7}{19}\times\dfrac{1}{3}+\dfrac{7}{19}\times\dfrac{2}{3}\)

\(=\dfrac{7}{19}\times\left(\dfrac{1}{3}+\dfrac{2}{3}\right)=\dfrac{7}{19}\times\dfrac{3}{3}=\dfrac{7}{19}\times1=\dfrac{7}{19}\)

Answer 5

a, \(\dfrac{3}{5}\) x \(\dfrac{8}{27}\) x \(\dfrac{5}{3}\)

= \(\dfrac{8}{27}\) x ( \(\dfrac{3}{5}\) x \(\dfrac{5}{3}\) )

= \(\dfrac{8}{27}\) x        1

=            \(\dfrac{8}{27}\)

b, \(\dfrac{7}{19}\) x \(\dfrac{1}{3}\) + \(\dfrac{7}{19}\) x \(\dfrac{2}{3}\)

= \(\dfrac{7}{19}\) x ( \(\dfrac{1}{3}\) + \(\dfrac{2}{3}\) )

= \(\dfrac{7}{19}\) x        1

=         \(\dfrac{7}{19}\)