a) ta có:  \(1-\frac{2012}{2013}=\frac{1}{2013}\)

                 \(1-\frac{2013}{2014}=\frac{1}{2014}\)

mà \(\frac{1}{2013}>\frac{1}{2014}\) nên   \(\frac{2013}{2014}>\frac{2012}{2013}\)

sao giống lớp 4 thế ta

\(\dfrac{1313}{1717}=\dfrac{101x13}{101x17}=\dfrac{13}{17}\)

\(\dfrac{131313}{171717}=\dfrac{10101x13}{10101x17}=\dfrac{13}{17}\)

Vậy \(\dfrac{1313}{1717}=\dfrac{131317}{171717}\)

\(\dfrac{1313}{1717}và\dfrac{131313}{171717}\\ \dfrac{1313}{1717}=\dfrac{13}{17}\\ \dfrac{131313}{171717}=\dfrac{13}{17}\\ \Rightarrow\dfrac{1313}{1717}=\dfrac{131313}{171717}\)

+ \(\frac{2000}{2001}=\frac{2001-1}{2001}=1-\frac{1}{2001}\)

+ \(\frac{2001}{2002}=\frac{2002-1}{2002}=1-\frac{1}{2002}\)

+ \(\frac{1}{2001}>\frac{1}{2002}\Rightarrow1-\frac{1}{2001}

\(1-\frac{2000}{2001}=\frac{1}{2001}\)

\(1-\frac{2001}{2002}=\frac{1}{2002}\)

Vì \(\frac{1}{2001}>\frac{1}{2002}\) nên  \(\frac{2000}{2001}

Ta có: 2000/2001 = 1 - 1/2001

          2001/2002 = 1 - 1/2002

mà 1/2001 > 1/2002

  --> 1 - 1/2001 < 1 - 1/2002

-->      2000/2001 < 2001/2002

Ta thấy: \(\frac{2000}{2001}=1-\frac{1}{2001}\)

              \(\frac{2001}{2002}=1-\frac{1}{2002}\)

Vì: \(\frac{1}{2001}>\frac{1}{2002}\)

\(\Rightarrow\frac{2000}{2001}< \frac{2001}{2002}\)

Ta có: 201/301>201/308; 201/308>199/308

\(\Rightarrow\)201/301>199/308

Ta có : 

\(\frac{201}{301}>\frac{201}{308}\left(301< 308\right)\)

Mà \(\frac{199}{308}< \frac{201}{308}\left(199< 201\right)\)

\(\Rightarrow\frac{201}{301}>\frac{199}{308}\)

Chúc bạn học tốt !!!! 

Không quy đồng tử số và mẫu số , hãy so sánh các phân số sau : 2012/ 2013 và 1998 / 1999

 2012/ 2013 > 1998 / 1999

DỄ MÀ

2012/2013>1998/1999 HOẶC 2012/2013 < 1998/1999

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