Question

Các phân số sau có bằng nhau không? Tại sao?

$\frac{4}{6}$ ;  $\frac{8}{{12}}$ ;  $\frac{{10}}{{15}}$  ;  $\frac{{14}}{{21}}$

Answer 1

$\frac{4}{6} = \frac{{4:2}}{{6:2}} = \frac{2}{3}$  ;   $\frac{8}{{12}} = \frac{{8:4}}{{12:4}} = \frac{2}{3}$

$\frac{{10}}{{15}} = \frac{{10:5}}{{15:5}} = \frac{2}{3}$  ;   $\frac{{14}}{{21}} = \frac{{14:7}}{{21:7}} = \frac{2}{3}$

Vậy các phân số đã cho bằng nhau.

Answer 2

\(\dfrac{4}{6}=\dfrac{4:2}{6:2}=\dfrac{2}{3};\dfrac{8}{12}=\dfrac{8:4}{12:4}=\dfrac{2}{3}\)

\(\dfrac{10}{15}=\dfrac{10:5}{15:5}=\dfrac{2}{3};\dfrac{14}{21}=\dfrac{14:7}{21:7}=\dfrac{2}{3}\)

Do đó: \(\dfrac{4}{6}=\dfrac{8}{12}=\dfrac{10}{15}=\dfrac{14}{21}\)