a) Vì 5/24 và 5/8 đều có tử số là 5 nên 24 > 8 nên 5/24 < 5/8

b)3/13 = 6/26 ; giữ nguyên 4/26

Vậy 3 /13 > 4/26

c)11/53 = 22 /106 ; giữ nguyên 22/37

Vậy 11/53 < 22/37

d)13/25 = 52/100 ; giữ nguyên 53/100

Vậy 12/25 < 53/100

 a) \(\frac{{ - 3}}{8} = \frac{{ - 3.3}}{{8.3}} = \frac{{ - 9}}{{24}}\)

Vì -9 < -5 nên \(\frac{{ - 9}}{{24}} < \frac{{ - 5}}{{24}}\)

Vậy \(\frac{{ - 3}}{8} < \frac{{ - 5}}{{24}}\).

b) Cách 1: \(\frac{{ - 2}}{{ - 5}} = \frac{2}{5}; \frac{3}{{ - 5}} = \frac{-3}{{5}}\)

Vì 2 > -3 nên \(\frac{2}{5} > \frac{-3}{{5}}\)

Vậy \(\frac{{ - 2}}{{ - 5}} > \frac{3}{{ - 5}}\).

Cách 2: \(\frac{{ - 2}}{{ - 5}} = \frac{2}{5} > 0\) mà \(\frac{3}{{ - 5}} < 0\)

\(\Rightarrow\) \(\frac{{ - 2}}{{ - 5}} > \frac{3}{{ - 5}}\).

c) \(\frac{{ - 3}}{{ - 10}} = \frac{3}{{10}} = \frac{{3.2}}{{10.2}} = \frac{6}{{20}}\)

\(\frac{{ - 7}}{{ - 20}} = \frac{7}{{20}}\)

Vì 6 < 7 nên \(\frac{6}{{20}} < \frac{7}{{20}}\) nên \(\frac{{ - 3}}{{ - 10}} < \frac{{ - 7}}{{ - 20}}\).

d) \(\frac{{ - 5}}{4} = \frac{{ - 5.5}}{{4.5}} = \frac{{ - 25}}{{20}}; \frac{{ 23}}{{-20}}=\frac{{-23}}{{20}} \)

Vì -25 < -23 nên \( \frac{{ - 25}}{{20}} < \frac{{-23}}{{20}} \)

Vậy \(\frac{{ - 5}}{4} < \frac{{23}}{{ - 20}}\).

a: 26/39>0>-24/32

b: -5/3<-1<-10/-11

a: \(\dfrac{-8}{31}=\dfrac{-8\cdot101}{31\cdot101}=\dfrac{-808}{3131}\)

\(\dfrac{-789}{3131}=\dfrac{-789}{3131}\)

b: Thiếu phân số thứ hai rồi bạn

c: \(\dfrac{1}{n}=\dfrac{n+1}{n\left(n+1\right)}\)

\(\dfrac{1}{n+1}=\dfrac{n}{n\left(n+1\right)}\)

2/

a/ \(\dfrac{7}{10}=\dfrac{7.15}{10.15}=\dfrac{105}{150}\)

\(\dfrac{11}{15}=\dfrac{11.10}{15.10}=\dfrac{110}{150}\)

-Vì \(\dfrac{105}{150}< \dfrac{110}{150}\)(105<110)nên \(\dfrac{7}{10}< \dfrac{11}{15}\)

b/ \(\dfrac{-1}{8}=\dfrac{-1.3}{8.3}=\dfrac{-3}{24}\)

-Vì \(\dfrac{-3}{24}>\dfrac{-5}{24}\left(-3>-5\right)\)nên\(\dfrac{-1}{8}>\dfrac{-5}{24}\)

c/\(\dfrac{25}{100}=\dfrac{25:25}{100:25}=\dfrac{1}{4}\)

\(\dfrac{10}{40}=\dfrac{10:10}{40:10}=\dfrac{1}{4}\)

-Vì \(\dfrac{1}{4}=\dfrac{1}{4}\)nên\(\dfrac{25}{100}=\dfrac{10}{40}\)

a/ \(\dfrac{7}{10}< \dfrac{11}{15}\)

c/ \(\dfrac{25}{100}=\dfrac{10}{40}\)

b: 29/36=58/72=1-14/72

25/39=1-14/39

14/72<14/39

=>-14/72>-14/39

=>1-14/72>1-14/39

=>29/36>25/39

=>-29/36<-25/39

a: 21/36<24/36

=>21/36<2/3

=>21/36<26/39

mà 26/39<26/35

nên 21/36<26/35

thanks bạn nhé

Bài 1:

\(\dfrac{-5}{18}=\dfrac{-20}{72};\dfrac{7}{-24}=\dfrac{-21}{72}.\)

\(\dfrac{-15}{-40}=\dfrac{3}{8}=\dfrac{9}{24};\dfrac{24}{-72}=\dfrac{-1}{3}=\dfrac{-8}{24}.\)

Bài 3:

a) \(\dfrac{2}{3}h=\dfrac{8}{12}h;\dfrac{3}{4}h=\dfrac{9}{12}h.\Rightarrow\dfrac{2}{3}h< \dfrac{3}{4}h.\)

b) \(\dfrac{4}{5}km/h=\dfrac{8}{10}km/h;\dfrac{9}{10}km/h.\Rightarrow\dfrac{4}{5}km/h< \dfrac{9}{10}km/h.\)

a) Vì 39 < 54 nên -39 > -54

b) Vì 3 179 < 3 279 nên - 3 179 > - 3 279.

a,-11/14 >5/-14

vì -11/14<1;5/-14<1

b,14/26<25/45

vì 14/26=7/13=7*9/13*9=63/117;25/45=5/9=5*13/9*13=65/117

c,-18/28;58/-78(tương tự cậu b nha)

a) Ta có : \(\frac{5}{-14}=\frac{-5}{14}\) mà -11< -5 nên => \(\frac{-11}{14}< \frac{-5}{14}\) hay \(\frac{-11}{14}< \frac{5}{-14}\)

b) Ta có :\(\frac{14}{26}=\frac{14:2}{26:2}=\frac{7}{13}\)( cái này là phần rút gọn nha '-')

                 \(\frac{25}{45}=\frac{5}{9}\)

Lại có : \(\frac{7}{13}=\frac{63}{117}\); \(\frac{5}{9}=\frac{65}{117}\) mà 63<65 => \(\frac{63}{117}< \frac{65}{117}\) hay \(\frac{14}{26}< \frac{25}{45}\)

c) Ta cs : \(\frac{-18}{28}=\frac{-9}{14}\); \(\frac{58}{-78}=\frac{-58}{78}=\frac{-29}{39}\)

Lại có : \(\frac{-9}{14}=\frac{-351}{546};\frac{-29}{39}=\frac{-406}{546}\) mà -351 > - 406 => \(\frac{-351}{546}>\frac{-406}{546}\) hay \(\frac{-18}{28}>\frac{58}{-78}\)

cậu có thể tham khảo nha, chúc cậu học tốt ^^