7/8 x 1/4 + 7/8 x 2/4 + 7/8

=7/8 x\(\left(\dfrac{1}{4}+\dfrac{2}{4}\right)\) + 7/8

=7/8 x 3/4 + 7/8

=7/8 x \(\left(\dfrac{3}{4}+1\right)\)

=7/8 x 7/4

=49/32

`7/8 xx 1/4 + 7/8 xx 2/4 + 7/8`

`= 7/8 xx 1/4 + 7/8 xx 2/4 + 7/8xx1`

`= 7/8 xx (1/4 +2/4+1)`

`= 7/8 xx ( 3/4 + 4/4)`

`= 7/8 xx 7/4`

`= 49/32`

` @ nkhanh`

7/8 x 1/4 + 7/8 x 2/4 + 7/8

=7/8 x 1/4 + 7/8 x 2/4 + 7/8 x 4/4

= 7/8x(1/4+2/4+4/4)

=7/8x7/4

=49/32

\(\left(\dfrac{2}{7}+\dfrac{5}{7}\right)+\left(\dfrac{3}{5}+\dfrac{2}{5}\right)+\left(\dfrac{3}{8}+\dfrac{4}{8}+\dfrac{1}{8}\right)+\left(\dfrac{1}{9}+\dfrac{8}{9}\right)=1+1+1+1=4\)

(2/7 + 5/7) + (3/5 + 2/5) + (3/8 + 4/8 + 1/8) + (1/9 + 8/9 )

= 1  +       1                   +         1             +        1         =  4

6/7 * 5/8*7/3*7/6*8/5

= 6*5*7*7*8 /7*8*3*6*5

=1*1*7*1*1/1*1*3*1*1

= 7/3 

\(\dfrac{4}{5}\times\left(\dfrac{5}{4}-\dfrac{5}{7}\right)\)

\(=\dfrac{4}{5}\times\left(\dfrac{35}{28}-\dfrac{20}{28}\right)\)

\(=\dfrac{4}{5}\times\dfrac{15}{28}\)

\(=\dfrac{3}{7}\)

__

\(\dfrac{5}{8}\times\dfrac{9}{7}+\dfrac{5}{8}\times\dfrac{5}{7}\)

\(=\dfrac{5}{8}\times\left(\dfrac{9}{7}+\dfrac{5}{7}\right)\)

\(=\dfrac{5}{8}\times2=\dfrac{10}{8}=\dfrac{5}{4}\)

Bài làm

   \(\frac{7}{15}x\frac{3}{8}+\frac{7}{15}x\frac{5}{8}\)

= \(\frac{7}{15}x\left(\frac{3}{8}+\frac{5}{8}\right)\)

= \(\frac{7}{15}x\frac{8}{8}\)

= \(\frac{7}{15}x1\)

= \(\frac{7}{15}\)

# Chúc bạn học tốt #

\(\frac{7}{15}\cdot\frac{3}{8}+\frac{7}{15}\cdot\frac{5}{8}\)

\(=\frac{7}{15}\cdot(\frac{3}{8}+\frac{5}{8})\)

\(=\frac{7}{15}\cdot1=\frac{7}{15}\)

\(\frac{7}{15}\times\frac{3}{8}+\frac{7}{15}\times\frac{5}{8}\)

\(=\frac{7}{15}\times\left(\frac{3}{8}+\frac{5}{8}\right)\)

\(=\frac{7}{15}\times1\)

\(=\).....................

Tự làm tiếp nhé!

giúp mik zứi😭😭😭

1200-31/40=47969/40

câu 2 =45/56+25/56=(45+25)/56=70/56=5/4