Question

So sánh phân số:

\(a,\dfrac{-4}{5}và\dfrac{8}{-10}\)

\(b,\dfrac{2}{3}và\dfrac{3}{4}\)

Answer 1

a) \(\dfrac{-4}{5}\)và \(\dfrac{8}{-10}\)

Ta có \(\dfrac{8}{-10}\)=\(\dfrac{-4}{5}\)

=>\(\dfrac{-4}{5}\)=\(\dfrac{8}{-10}\)

b) \(\dfrac{2}{3}\)và \(\dfrac{3}{4}\)

Ta có: \(\dfrac{2}{3}=\dfrac{8}{12}\);\(\dfrac{3}{4}=\dfrac{9}{12}\)

Mà \(\dfrac{8}{12}< \dfrac{9}{12}\)

=>\(\dfrac{2}{3}\)<\(\dfrac{3}{4}\)

Answer 2

a) \(\dfrac{-4}{5}và\dfrac{8}{-10}\)

Quy đồng: \(\dfrac{-4}{5}=\dfrac{-8}{10}\)

Ta có :\(\dfrac{-8}{10}=\dfrac{8}{-10}\)

⇒ \(\dfrac{-4}{5}=\dfrac{8}{-10}\)

b) \(\dfrac{2}{3}và\dfrac{3}{4}\)

Quy đồng: \(\dfrac{2}{3}=\dfrac{8}{12}\) ; \(\dfrac{3}{4}=\dfrac{9}{12}\)

Ta có: \(\dfrac{8}{12}< \dfrac{9}{12}\)

⇒ \(\dfrac{2}{3}< \dfrac{3}{4}\)