A.4/25 < 25/4

B. 2/9 và  < 9/2

A.4/25 < 25/4

 B. 2/9  <9/2

So sánh phân số bằng phân số trung gian

Vì \(\dfrac{1973}{2010}\) > \(\dfrac{1973}{2011}\)  > \(\dfrac{1969}{2011}\) 

Vậy \(\dfrac{1973}{2010}\) >  \(\dfrac{1969}{2011}\) 

18/36 và 7/6

rút gọn phấn số 18/36 = 3/6

vậy 3/6 < 7/6 hoặc 18/36 < 7/6

18/26=1/2

1/2<1

7/6>1

1/2<7/6

HT

Ta có : \(\frac{18}{36}=\frac{3.6}{6.6}=\frac{3}{6}\)

\(\frac{3}{6}< \frac{7}{6}\)

\(\Rightarrow\frac{18}{36}< \frac{7}{6}\)

Hoặc 

\(\frac{18}{36}< 1\left(18< 36\right)\)

\(\frac{7}{6}>1\left(7>6\right)\)

\(\Rightarrow\frac{18}{36}< \frac{7}{6}\)

HT

99/100 = 100/99

\(\dfrac{99}{100}=1-\dfrac{1}{100}\)

\(\dfrac{100}{99}=1+\dfrac{1}{99}\)

\(\dfrac{100}{99}>\dfrac{99}{100}\)

xin TICH. chúc bạn học tốt

96/104 = 1 - 8/104

94/102 = 1 - 8/102

Do 102 < 104 ⇒ 8/104 < 8/102

⇒ 1 - 8/104 > 1 - 8/102

Vậy 96/104 > 94/102

Rút gọn ta được:

\(\dfrac{96}{104}=\dfrac{12}{13};\dfrac{94}{102}=\dfrac{47}{51}\)

Quy đồng:

\(\dfrac{12}{13}=\dfrac{612}{663};\dfrac{47}{51}=\dfrac{611}{663}\)

So sánh: \(\dfrac{612}{663}>\dfrac{611}{663}\)

Vậy \(\dfrac{96}{104}>\dfrac{94}{102}\).

\(\dfrac{12}{17}>\dfrac{1}{2};\dfrac{5}{36}< \dfrac{1}{2}\\ \Rightarrow\dfrac{12}{17}>\dfrac{5}{36}\)

\(\dfrac{12}{17}\) \(>\) \(\dfrac{5}{36}\)

Ta có \(\left\{{}\begin{matrix}\dfrac{4}{3}=\dfrac{32}{24}\\\dfrac{9}{8}=\dfrac{27}{24}\end{matrix}\right.\) mà \(32>27\) nên \(\dfrac{4}{3}>\dfrac{9}{8}\)