Question

so sánh phân số sau bằng hai cách khác nhau :

a) \(\dfrac{3}{4}\) và \(\dfrac{4}{3}\)                        b) \(\dfrac{11}{8}\) và \(\dfrac{7}{10}\)

giúp em nhanh bài này với ạ huhu

Answer 1

Ta có : `3/4 < 1`

`4/3 > 1`

`=> 3/4 < 4/3`

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Ta có : `11/8 > 1`

`7/10 < 1`

`=> 11/8 > 7/10`

Answer 2

\(a)\dfrac{3}{4}và\dfrac{4}{3}\)

\(C1:\)

\(\dfrac{3}{4}=\dfrac{3\times3}{4\times3}=\dfrac{9}{12};\dfrac{4}{3}=\dfrac{4\times4}{3\times4}=\dfrac{16}{12}\)

 vì \(\dfrac{9}{12}< \dfrac{16}{12}hay\dfrac{3}{4}< \dfrac{4}{3}\)

\(C2:\)

\(\dfrac{3}{4}< 1;\dfrac{4}{3}>1\) nên \(\dfrac{3}{4}< \dfrac{4}{3}\)

\(b)\dfrac{11}{8}và\dfrac{7}{10}\)

\(C1:\)

\(\dfrac{11}{8}=\dfrac{11\times5}{8\times5}=\dfrac{55}{40};\dfrac{7}{10}=\dfrac{7\times4}{10\times4}=\dfrac{28}{40}\) vì \(\dfrac{55}{40}>\dfrac{28}{40}hay\dfrac{11}{8}>\dfrac{7}{10}\)

\(C2:\)

\(\dfrac{11}{8}>1;\dfrac{7}{10}< 1\) nên \(\dfrac{11}{8}>\dfrac{7}{10}\)