`4/6+7/13+17/9+19/13+1/9+14/6`

`=(4/6+14/6)+(7/13+19/13)+(17/9+1/9)`

`=18/6+26/13+18/9`

`=3+2+2`

`=7`

5/14*7/13*26/25

=7/14*5/25*26/13

=1/2*1/5*2

=1/5

5/14\(\times\)7/13\(\times\)26/25

=\(\frac{5\times7\times26}{14\times13\times25}\)(rút gọn)

=1/5

a,3/5*7/9+11/9*3/5-3/10=3/5*(7/9+11/9)-3/10

=3/5*18/9-3/10

=3/5*2-3/10

=6/5-3/10

=12/10-3/10

=9/10

b,14/13:1/2+3/13*2-2*7/13=14/13*2+3/13*2-2*7/13

=2*(14/13+3/13-7/13)

=2*10/13

=20/13

a/ ( 7/9 + 11/9 ) x 3/5 - 3/10

 =    2 x 3/5 - 3/10

=    6/5  - 3/10

 =    9/10

b/ 14/13 :  1/2 + 3/13 x 2 - 2 x 7/13

14/13 x 2/1 + 3/13 x 2 - 2 x 7/13

2 x ( 14/13 + 3/13 - 7/13 )

2 x 10/13

20/13

1*3+5*7+9*11+...+99*101

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

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

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

\(=3+2-2\)

\(=3\)

bằng 3

3

chuc ban hoc tot nhe

ko chép đề bài nhé

=2/26+12/13+4/7+9/21+3/4+25/100

=2/26+24/26+12/21+9/21+75/100+25/100

=1+1+1=3

\(\frac{4}{6}+\frac{7}{13}+\frac{17}{9}+\frac{19}{13}+\frac{1}{9}+\frac{14}{6}\)

\(=\left(\frac{4}{6}+\frac{14}{6}\right)+\left(\frac{7}{13}+\frac{19}{13}\right)+\left(\frac{17}{9}+\frac{1}{9}\right)\)

\(=3+2+2=7\)

 4/6 + 7/13 + 17/9 + 19/13 + 1/9 + 14/6. = ( 4/6 + 14/6 ) + ( 7/13 + 19/13 ) + ( 17/9 + 1/9 ). = 18/6 + 26/13 + 18/9. = 3 + 2 + 2 = 7.

\(\frac{4}{6}+\frac{7}{13}+\frac{17}{9}+\frac{19}{13}+\frac{1}{9}+\frac{14}{6}=\left(\frac{4}{6}+\frac{14}{6}\right)+\left(\frac{7}{13}+\frac{19}{13}\right)\)\(+\left(\frac{17}{9}+\frac{1}{9}\right)=\frac{18}{6}+\frac{26}{13}+\frac{18}{9}=3+2+2=7\)

\(\frac{14}{9}:\frac{13}{12}+\frac{4}{3}:\frac{13}{12}\)

\(=\frac{14}{9}\cdot\frac{12}{13}+\frac{4}{3}\cdot\frac{12}{13}\)

\(=\left(\frac{14}{9}+\frac{4}{3}\right)\cdot\frac{12}{13}\)

\(=\frac{26}{9}\cdot\frac{12}{13}=\frac{8}{3}\)