a ) -33/56

b )-17/63

c ) 18/5

a ) - 33/56

b ) - 17/63

c ) 18/5

  a.6/8 * 7/6

  =6*7/8*6

   =42/48

    =21/24(rut gọn)

    =7/8(rút gọn)

 b.6*7/9 

    =6*7/9

    =42/9

    =14/3(rút gọn)

 c.4/6 : 8/2

   =4/6 * 2/8

   =4*2/6*8

   =8/48

   =4/12=2/6=1/3(rut gọn)

   Đúng thì k cho mình nha

a)\(\frac{6}{8}\times\frac{7}{6}=\frac{6\times7}{8\times6}=\frac{42}{48}=\frac{7}{8}\)

b)\(6\times\frac{7}{9}=\frac{6}{1}\times\frac{7}{9}=\frac{6\times7}{1\times9}=\frac{42}{9}=\frac{14}{3}\)

c)\(\frac{4}{6}\div\frac{8}{2}=\frac{4}{6}\times\frac{2}{8}=\frac{4\times2}{6\times8}=\frac{8}{48}=\frac{1}{6}\)

#Học tốt!!!

~NTTH~

\(6-\left(\frac76+\frac{7}{18}\right)\)

\(=6-\left(\frac{7\times3}{6\times3}+\frac{7}{18}\right)\)

\(=6-\left(\frac{21}{18}+\frac{7}{18}\right)\)

\(=6-\left(\frac{21+7}{18}\right)\)

\(=6-\frac{28}{18}\)

\(=6-\frac{28:2}{18:2}\)

\(=6-\frac{14}{9}\)

\(=\frac{6\times9}{1\times9}-\frac{14}{9}\)

\(=\frac{36}{9}-\frac{14}{9}\)

\(=\frac{54-14}{9}\)

\(=\frac{40}{9}\)

cong hai cái số trong ngoac rồi lấy 6 đổi ra 6'1 trừ đi

\(\frac{1}{2}:\frac{3}{2}:\frac{5}{4}:\frac{6}{5}:\frac{7}{6}:\frac{8}{7}\)

\(=\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{4}{5}\cdot\frac{5}{6}\cdot\frac{6}{7}\cdot\frac{7}{8}\)

\(=\frac{1\cdot\left(2\cdot5\cdot6\cdot7\right)}{8\cdot3\cdot\left(2\cdot5\cdot6\cdot7\right)}\)

\(=\frac{1}{24}\)

\(\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{3}{4}\cdot\frac{4}{5}\cdot\frac{5}{6}\cdot\frac{6}{7}\cdot\frac{7}{8}\cdot\frac{8}{9}\cdot\frac{9}{10}\)

\(=\frac{1\cdot\left(2\cdot3\cdot4\cdot5\cdot6\cdot7\cdot8\cdot9\right)}{\left(2\cdot3\cdot4\cdot5\cdot6\cdot7\cdot8\cdot9\right)\cdot10}\)

\(=\frac{1}{10}\)

a, 5x7 / 6x7 và 6x6 / 7x6

= 30/42 và 36/42

5 phân số nằm giữa gồm có: 31/42 , 32/42 , 33/42 , 34/42 , 35/42

b, bạn làm tương tự nhé (con này lười rồi)

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\(a.\dfrac{3\times4\times7}{12\times8\times9}=\dfrac{3\times4\times7}{3\times4\times4\times2\times9}\\ =\dfrac{7}{4\times2\times9}=\dfrac{7}{72}\\ b.\dfrac{4\times5\times6}{12\times10\times8}=\dfrac{4\times5\times2\times3}{4\times3\times5\times2\times4\times2}=\dfrac{1}{8}\\ c.\dfrac{5\times6\times7}{12\times14\times15}=\dfrac{5\times6\times7}{2\times6\times7\times2\times5\times3}\\ =\dfrac{1}{2\times2\times3}=\dfrac{1}{12}\)

\(\frac{7}{6}-\frac{2}{6}=\frac{5}{6}\)

k cho mình nha !

chúc bạn học tốt!!!

Số cần tìm là :

\(\frac{7}{6}-\frac{2}{6}=\frac{5}{6}\)

Đáp số : \(\frac{5}{6}\)

Vậy.............

4/7 x 5/6+ 3/7x5/6

= ( 4/7+3/7)x5/6

= 1 x5/6

=5/6

\(\frac{4}{7}\times\frac{5}{6}+\frac{3}{7}\times\frac{5}{6}\)

\(=\frac{5}{6}\times\left(\frac{3}{7}+\frac{4}{7}\right)\)

\(=\frac{5}{6}\times\frac{7}{7}=\frac{5}{6}\times1=\frac{5}{6}\)

a, \(\frac{5}{7}+\frac{8}{7}=\frac{13}{7}\)

b,\(\frac{9}{8}-\frac{3}{8}=\frac{6}{8}\)

c,\(\frac{6}{1}:\frac{6}{5}=\frac{6}{1}\cdot\frac{5}{6}=\frac{30}{6}=5\)

~~~Hok tốt ~~~

a,\(\frac{13}{7}\)

b,\(\frac{6}{8}\)= \(\frac{3}{4}\)

c,\(\frac{9}{7}\)

d,5