Cách 1 :

\(\frac{-60}{-72}\)\(=\frac{60}{72}=\frac{5}{6}\)

\(\frac{-14}{21}=\frac{-2}{3}\)

Vì \(\hept{\begin{cases}6⋮3\\6⋮6\end{cases}}\Rightarrow BCNN\left(6;3\right)=6\Rightarrow MC=6\)

Có: \(\frac{-2}{3}=\frac{\left(-2\right).2}{3.2}=\frac{-4}{6}\)giữ nguyên \(\frac{5}{6}\).

Vì - 4 < 5 nên \(\frac{-4}{6}< \frac{5}{6}\)hay \(\frac{-14}{21}< \frac{-60}{-72}\)

C2 : Thấy : \(\frac{-14}{21}< 0;\frac{-60}{-72}=\frac{60}{72}>0\)

\(\Rightarrow\frac{-14}{21}< \frac{-60}{-72}\)

Cách 1\(\frac{-14}{21}=\frac{-14:7}{21:7}\frac{2}{3}\)

\(\frac{-60}{-72}=\frac{-60:(-12)}{-72:(-12)}=\frac{5}{6}\)

Cách 2 : Tự làm

Bài 52 :

a) 14/21 = 2/3 và 60/72 = 5/6

Vì 2/3 = 4/6 < 5/6 nên 2/3 < 5/6

Bài 53 :

a) Vì 200 < 314 nên 17/200 > 17/314

b) Ta có 11/54 < 11/37 < 22/37 nên 11/54 < 22/37

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\(\dfrac{14}{21};\dfrac{60}{72}\)

\(\dfrac{60}{72}=\dfrac{5}{6}=\dfrac{5\cdot21}{6\cdot21}=\dfrac{105}{126}\)

\(\dfrac{14}{21}=\dfrac{14\cdot6}{21\cdot6}=\dfrac{84}{126}\)

\(\dfrac{84}{123}< \dfrac{105}{126}\Rightarrow\dfrac{14}{21}< \dfrac{60}{72}\)

\(\dfrac{38}{133};\dfrac{129}{344}\)

\(\dfrac{38}{133}=\dfrac{19}{7}=\dfrac{19\cdot8}{7\cdot8}=\dfrac{152}{56}\)

\(\dfrac{129}{344}=\dfrac{3}{8}=\dfrac{3\cdot7}{8\cdot7}=\dfrac{21}{56}\)

\(\dfrac{152}{56}>\dfrac{21}{56}\Rightarrow\dfrac{38}{133}>\dfrac{129}{344}\)

Chịu nhé

\(\dfrac{60}{72}>\dfrac{14}{21}\)              \(\dfrac{19}{31}>\dfrac{17}{35}\)                   \(\dfrac{18}{53}>\dfrac{26}{78}\)    

ta có

\(\frac{14}{21}=\frac{2}{3}=\frac{4}{6}\)

\(\frac{60}{72}=\frac{5}{6}\)

\(\Rightarrow\frac{14}{21}< \frac{60}{72}\)

phần sau tự làm nhé .chúc bạn học tốt

*14/21=2/3=4/6

60/72=5/6

vậy 4/6<5/6 suy ra 14/21<60/72

*2/3=8/12

1/4=3/12

vậy 8/12>3/12 suy ra 2/3>1/4

31¹⁷<32¹⁷; 32¹⁷=(2⁵)¹⁷=2⁵¹

17¹⁴>16¹⁴; 16¹⁴=(2⁴)¹⁴=2⁵⁶

Vì 2⁵¹<2⁵⁶=>32¹⁷<16¹⁴

=>31¹⁷<17¹⁴

\(a,\frac{2}{3}>\frac{1}{4}\)

\(b,\frac{7}{10}< \frac{7}{8}\)

\(c,\frac{6}{7}>\frac{3}{5}\)

\(d,\frac{14}{21}< \frac{60}{72}\)

\(e,\frac{16}{9}< \frac{24}{13}\)

\(g,\frac{27}{82}< \frac{26}{75}\)

a 2/3 > 1/4

b 7/10 < 7/8

c6/7 > 3/5

d14/21 < 60/72

e16/9 < 24/13

g27/82<26/75

a) Ta có: 14/25 < 15/25 = 3/5

Do: 1 - 3/5 = 2/5; 1 - 5/7 = 2/7

Mà: 2/5 > 2/7  => 3/5 < 5/7

=> 14/25 < 3/5 < 5/7

Vậy: 14/25 < 5/7

b)13/60 < 15/60 = 1/4 
27/100 > 25/100 = 1/4 
Vậy 13/60 < 27/100 
c)  1993/1995 + 2/1995 = 1 
997/998 + 1/998 = 997/998 + 2/1996 =1 
Mà 2/1996 < 2/1995 => 997/998 > 1993/1995 
Vậy 997/998 > 1993/1995
d) 47/15 và 66/21 
47/15 = 3 + 2/15 
66/21 = 3 + 2/21 
Mà 2/15 > 2/21 => 47/15 < 66/21

Vay cau D la nhu the nao bna 47/15 < 65/21 nhu nay ak