3/7×25/19-2/7×18/19

75/133-36-133

39/133

Yêu cầu là gì bạn???

tính bằng cách thuận tiện nhất ạ 

Uk, vậy cái dấu gì ở giữa chữ x và số 25/19 vậy bạn?? ^ ^

a )     \(\frac{5}{11}\times\frac{7}{25}\times\frac{15}{11}\times\frac{1}{5}\)

\(=\frac{5\times7\times15\times1}{11\times25\times11\times5}\)

\(=\frac{1\times7\times3\times1}{11\times5\times11\times1}\)

\(=\frac{21}{\left(10\times5+5\times1\right)\times11}\)

\(=\frac{21}{55\times11}\)

\(=\frac{21}{55\times10+55}\)

\(=\frac{21}{550+55}\)

\(=\frac{21}{605}\)   ( quá đơn giản ) 

\(\)

A) \(\frac{5}{11}\times\frac{7}{25}-\frac{15}{11}\times\frac{1}{5}\)

\(=\frac{5\times7}{11\times25}-\frac{15\times1}{11\times5}\)

\(=\frac{35}{10\times25+25}-\frac{15}{55}\)

\(=\frac{35}{250+25}-\frac{15}{55}\)

\(=\frac{35}{275}-\frac{15}{55}\)

\(=\frac{7}{55}-\frac{15}{55}\)

\(=\frac{7-15}{55}\)

\(=\frac{-8}{55}\)

bài ở dưới mới đúng nhà ( bài không có chữ đơn giản quá ) 

7/19x(1/3+2/3)

=7/19x1

=7/19

NHỚ K CHO MÌNH NẾU ĐÚNG NHÉ

= 7/19x(1/3+2/3)

= 7/19x1

= 7/19

:)))))))

\(\dfrac{7}{19}\times\dfrac{1}{3}+\dfrac{7}{13}\times\dfrac{2}{3}\)

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

\(=\dfrac{7}{19}\times1\)

\(=\dfrac{7}{19}\)

\(\dfrac{2}{3}+\dfrac{7}{13}-\dfrac{17}{9}+\dfrac{19}{13}-\dfrac{1}{9}+\dfrac{7}{3}\)

\(=\left(\dfrac{2}{3}+\dfrac{7}{3}\right)+\left(\dfrac{7}{13}+\dfrac{19}{13}\right)-\left(\dfrac{17}{9}+\dfrac{1}{9}\right)\)

\(=\dfrac{9}{3}+\dfrac{26}{13}-\dfrac{18}{9}\)

\(=3+2-2\)

\(=3\)

a, \(\frac{5}{11}\times\frac{7}{25}+\frac{15}{11}\times\frac{1}{5}\)

\(=\frac{5}{11}\times\frac{7}{25}+\frac{5}{11}\times\frac{3}{5}\)

\(=\frac{5}{11}\times\left(\frac{7}{25}+\frac{3}{5}\right)\)

\(=\frac{5}{11}\times\frac{22}{25}\)

\(=\frac{2}{5}\)

b, \(\frac{3}{7}\times\frac{25}{19}-\frac{1}{7}\times\frac{18}{19}\)

\(=\frac{1}{7}\times\frac{75}{19}-\frac{1}{7}\times\frac{18}{19}\)

\(=\frac{1}{7}\times\left(\frac{75}{19}-\frac{18}{19}\right)\)

\(=\frac{1}{7}\times3\)

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

a) 72 + 9 + 8 = ( 72 + 8 ) + 9

= 80 + 9

= 89

b)37 + 18 + 3 = ( 37 + 3 ) + 18

= 40 + 18

= 58

c) 48 + 26 + 4 = 48 + (26 + 4)

= 48 + 30

= 78

d)85 + 99 + 1 = 85 + ( 99 + 1 )

= 85 + 100 = 185

e) 67 + 98 + 33 = ( 67 + 33 ) + 98

= 100 + 98 = 198