2, dễ lắm em làm được mà

\(\frac{7}{21}+\frac{3}{21}+\frac{14}{21}+\frac{125}{175}+\frac{25}{175}\)

\(=\left(\frac{7}{21}+\frac{3}{21}\right)+\left(\frac{125}{175}+\frac{25}{175}\right)+\frac{14}{21}\)

\(=\frac{10}{21}+\frac{18}{21}+\frac{14}{21}\)

\(=\frac{10+18+14}{21}\)

\(=2\)

=24/21+150/175

<=>8/7+6/7=14/7=2

Đúng rồi đó, bằng 2.
Ta có: 7/21+3/21+14/21=7+3+14/21=24/21
125/175+25/175=125+25/175=150/175
Vì 24/21=8/7;150/175=6/7 nên 8/7+6/7=14/7=2
 

bằng 2 chứ sao trăng gì nữa

tư là 174

mau la 21

7/21+3/21+14/21+25/21+125/21=174/21 rút gọn là 22/3 nhé

tử 174 

Mẩu 21

7/21 + 125/75 + 14/21 + 25/175

= 1/3 + 5/3 + 2/3 + 1/7

= 8/3 + 1/7

= 59/21

\(\dfrac{7}{21}+\dfrac{125}{75}+\dfrac{14}{21}+\dfrac{25}{175}\)

\(=\left(\dfrac{7}{21}+\dfrac{14}{21}\right)+\dfrac{125}{75}+\dfrac{25}{175}\)

\(=\dfrac{21}{21}+\dfrac{5}{3}+\dfrac{1}{7}\)

\(=\dfrac{21}{21}+\dfrac{35}{21}+\dfrac{3}{21}\)

\(=\dfrac{59}{21}\)

??????????????????????????????????????????????????????????????????????????????????????????????????????????????????

89/28

777/444=7/4

120/105=8/7

50/175=2/7

7/4+8/7+2/7=7/4+5/7=49/28+20/28=69/28

777/444+120/105+50/175=89/28