8,36 x 5 x 0,2 = 8,36 x (5 x 0,2) = 8,36 x 1 = 8,36

… = 8,36 x (5 x 0,2)

= 8,36 x 1

= 8,36 

\(\dfrac{2}{7}\times\dfrac{1}{5}+0,2\times\dfrac{4}{7}\)

\(=\dfrac{2}{7}\times\dfrac{1}{5}+\dfrac{1}{5}\times\dfrac{4}{7}\)

\(=\dfrac{1}{5}\times\left(\dfrac{2}{7}+\dfrac{4}{7}\right)\)

\(=\dfrac{1}{5}\times\dfrac{6}{7}\)

\(=\dfrac{6}{35}\)

= 5 x 24 + 5 x 56 + 5 x 19 + 5 x 1

= 5 x (24 + 56 + 19 + 1)

= 5 x 100

= 500

= 5 x 24 + 5 x 56 + 5 x 19 + 5 x 1

= 5 x (24 + 56 + 19 + 1)

= 5 x 100

= 500

\(1975\times37+395\times5\times24-1975+3950\times15\)
\(=1975\times37+1975\times24-1975\times1+1975\times30\)
\(=1975\times\left(37+24-1+30\right)\)
\(=1975\times90=177750\)

250 x 5 x 0,2

= 250 x ( 5 x 0,2 )

= 250 x 1

= 250

0,29 x 8 x 1,25 

= 0,29 x ( 8 x 1,25 )

= 0,29 x 10

= 2,9

0,04 x 0,1 x 25

= ( 0,04 x 25 ) x 0,1 

= 1 x 01

= 0,1

250 x 5 x 0,2 

= 250 x 1

= 250

0,25 x 8 x 1,25

= 0,25 x 10 

= 2,5

0,04 x 0,1 x 25

= 0,04 x 2,5

= 0,1

Tôi có lời khen

\(\frac{19,8:0.2.44,44.2.13,2:0,25}{3,3.88,88:0,5.6,6:0,125.5}\) \(=\frac{19,8.5.44,44.2.13,2.4}{3,3.88,88.2.6,6.8.5}=\frac{3,3.6.5.44,44.2.6,66.4}{3,3.44,44.2.6,6.8.5}\)

                                                                                                                  \(=\frac{6.2.2}{8}=3\)

19,8:0.2.44,44.2.13,2:0,253,3.88,88:0,5.6,6:0,125.5  =19,8.5.44,44.2.13,2.43,3.88,88.2.6,6.8.5 =3,3.6.5.44,44.2.6,66.43,3.44,44.2.6,6.8.5 

                                                                                                                  =6.2.28 =3

*Ryeo*

\(\dfrac{7}{5}\times\dfrac{11}{24}\times\dfrac{5}{7}\times\dfrac{24}{55}\\ =\left(\dfrac{7}{5}\times\dfrac{5}{7}\right)\times\left(\dfrac{11}{24}\times\dfrac{24}{55}\right)\\ =1\times\dfrac{1}{5}\\ =\dfrac{1}{5}\)

\(\dfrac{7x11x5x24}{5x24x7x55}\)=\(\dfrac{11}{55}\)=\(\dfrac{1}{5}\)

= (7/5 x 5/7) x (11/24 x 24/55)

= 1 x 1/5

= 1/5