a)\(\dfrac{8}{15}< \dfrac{11}{15}< \dfrac{15}{15}< \dfrac{16}{15}< \dfrac{17}{15}< \dfrac{19}{15}\)

b)\(\dfrac{19}{42}< \dfrac{19}{35}< \dfrac{19}{21}< \dfrac{19}{19}< \dfrac{19}{17}\)

c)\(\dfrac{8}{10}< \dfrac{6}{7}< \dfrac{27}{25}< \dfrac{16}{14}\)

a) 8/15 ;  11/15 ; 15/15 ; 16/15 ; 17/15 ; 19/15

b) 19/42 19/35 ; 19/21 ; 19/19 ; 19/17

c) 8/10 ; 6/7 ; 27/25 ; 16/14

1. \(\frac{7}{39}=\frac{140}{780};\frac{11}{65}=\frac{132}{780};\frac{9}{52}=\frac{135}{780}\) và thứ tự tăng dần là : \(\frac{132}{780}< \frac{135}{780}< \frac{140}{780}\)

2. \(\frac{17}{20}=\frac{153}{180};-\frac{19}{30}=-\frac{114}{180};\frac{38}{45}=\frac{152}{180};-\frac{13}{10}=-\frac{130}{180}\) và thứ tự tăng dận là : 

\(-\frac{130}{180}< -\frac{114}{180}< \frac{152}{180}< \frac{153}{180}\)

.

Từ bé đến lớn : 13/14;14/15;15/16;16/17;17/18;18/19;19/20

Chúc bạn học tốt nhé!!!

1/4  ,   3/7   ,3/4   ,1   ,19/18    ,7/3

Mk nhanh nhất nha hih

Chưa chắc đâu!

a: \(\frac34=\frac{3\times30}{4\times30}=\frac{90}{120};\frac83=\frac{8\times40}{3\times40}=\frac{320}{120}\) ;

\(\frac58=\frac{5\times15}{8\times15}=\frac{75}{120};\frac{12}{5}=\frac{12\times24}{5\times24}=\frac{288}{120}\) ;

\(\frac12=\frac{1\times60}{2\times60}=\frac{60}{120};\frac43=\frac{4\times40}{3\times40}=\frac{160}{120}\)

TA có: 60<75<90<160<288<320

=>\(\frac{60}{120}<\frac{75}{120}<\frac{90}{120}<\frac{160}{120}<\frac{288}{120}<\frac{320}{120}\)

=>\(\frac12<\frac58<\frac34<\frac43<\frac{12}{5}<\frac83\)

=>\(\frac83>\frac{12}{5}>\frac43>\frac34>\frac58>\frac12\)

b: \(\frac78=1-\frac18;\frac23=1-\frac13;\frac56=1-\frac16\)

\(\frac{14}{15}=1-\frac{1}{15};\frac12=1-\frac12;\frac{18}{19}=1-\frac{1}{19}\)

Ta có: 2<3<6<8<15<19

=>\(\frac12>\frac13>\frac16>\frac18>\frac{1}{15}>\frac{1}{19}\)

=>\(-\frac12<-\frac13<-\frac16<-\frac18<-\frac{1}{15}<-\frac{1}{19}\)

=>\(-\frac12+1<-\frac13+1<-\frac16+1<-\frac18+1<-\frac{1}{15}+1<-\frac{1}{19}+1\)

=>\(\frac12<\frac23<\frac56<\frac78<\frac{14}{15}<\frac{18}{19}\)

a: \(\frac{5}{12}=\frac{5\times21}{12\times21}=\frac{105}{252}\)

\(\frac{7}{18}=\frac{7\times14}{18\times14}=\frac{98}{252}\)

\(\frac{-8}{21}=\frac{-8\times12}{21\times12}=\frac{-96}{252}\)

\(\frac{-5}{14}=\frac{-5\times18}{14\times18}=\frac{-90}{252}\)

mà -96<-90<98<105

nên \(-\frac{8}{21}<-\frac{5}{14}<\frac{7}{18}<\frac{5}{12}\)

b: \(\frac{7}{41}=\frac{7\times42}{41\times42}=\frac{294}{1722}\)

\(\frac{14}{105}=\frac{14\times21}{105\times21}=\frac{294}{2205}\)

\(\frac{49}{280}=\frac{49\times6}{280\times6}=\frac{294}{1680}\)

\(\frac{21}{126}=\frac{21\times14}{126\times14}=\frac{294}{1764}\)

mà 1680<1722<1764<2205

nên \(\frac{294}{1680}>\frac{294}{1722}>\frac{294}{1764}>\frac{294}{2205}\)

=>\(\frac{49}{280}>\frac{7}{41}>\frac{21}{126}>\frac{14}{105}\)

Thứ tự giảm dần : -27/28;-18/19;-7/8;-3/4;-2/3

mẫu số nào bé hơn thì phân số đó to hơn