So sánh hai phân số khác mẫu số

`(12/26+5/8)+7/13`

`=(6/13+5/8)+7/13`

`=(6/13+7/13)+5/8`

`=1+5/8=13/8`

`(12/26 +5/8) +7/13 `

`= 6/13 + 5/8 + 7/13`

`= (6/13 + 7/13) + 5/8`

`= 13/13 + 5/8`

`= 1 + 5/8 `

`= 8/8 + 5/8 `

`= 13/8`

\(\dfrac{5}{10}=\dfrac{1}{2}< 1;\dfrac{76898}{65334}>1\\ \Rightarrow\dfrac{76898}{65334}>\dfrac{5}{10}\)

5/10

a: 3/5>1/2

b: 5/6<7/8

c: 8/9<7/6

d: 9/4<7/3

e: 8/12=2/3

f: 77/99=7/9

\(\dfrac{3}{5}>\dfrac{1}{2}\)

\(\dfrac{5}{6}< \dfrac{7}{8}\)

\(\dfrac{8}{9}< \dfrac{7}{6}\)

\(\dfrac{9}{4}< \dfrac{7}{3}\)

\(\dfrac{8}{12}=\dfrac{2}{3}\)

\(\dfrac{77}{99}=\dfrac{7}{9}\)

\(\dfrac{3}{5}>\dfrac{1}{2}\)

\(\dfrac{5}{6}< \dfrac{7}{8}\)

\(\dfrac{8}{9}< \dfrac{7}{6}\)

\(\dfrac{9}{4}< \dfrac{7}{3}\)

\(\dfrac{8}{12}=\dfrac{2}{3}\)

\(\dfrac{77}{99}=\dfrac{7}{9}\)

\(\dfrac{65}{5}=13;24< \dfrac{5678}{234}< 25;\dfrac{456789}{5}=91357,8\)

Do đó: \(1< \dfrac{65}{5}< \dfrac{5678}{234}< \dfrac{456789}{5}\left(1\right)\)

\(\dfrac{6}{7}=\dfrac{6\cdot9}{7\cdot9}=\dfrac{54}{63};\dfrac{5}{9}=\dfrac{5\cdot7}{9\cdot7}=\dfrac{35}{63}\)

mà 54>35

nên \(1>\dfrac{6}{7}>\dfrac{5}{9}\)(2)

Từ (1),(2) suy ra \(\dfrac{5}{9}< \dfrac{6}{7}< \dfrac{65}{5}< \dfrac{5678}{234}< \dfrac{456789}{5}\)

Ta có: \(\dfrac{23}{24}-1=\dfrac{-1}{24}\)

\(\dfrac{24}{25}-1=\dfrac{-1}{25}\)

mà \(\dfrac{-1}{24}< \dfrac{-1}{25}\)

nên \(\dfrac{23}{24}-1< \dfrac{24}{25}-1\)

hay \(\dfrac{23}{24}< \dfrac{24}{25}\)

103/107=1-4/107

91/95=1-4/95

mà -4/107>-4/95

nên 103/107>91/95

6/5>5/8 nhé

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6/5>5/8

5 phần = 5 = \(\dfrac{5}{} \) :>

b

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