So sánh hai phân số khác mẫu số

Ta có: \(\dfrac{23}{24}-1=\dfrac{-1}{24}\)

\(\dfrac{24}{25}-1=\dfrac{-1}{25}\)

mà \(\dfrac{-1}{24}< \dfrac{-1}{25}\)

nên \(\dfrac{23}{24}-1< \dfrac{24}{25}-1\)

hay \(\dfrac{23}{24}< \dfrac{24}{25}\)

lỗi hình

phân số j mà có mỗi cái này zị 

103/107=1-4/107

91/95=1-4/95

mà -4/107>-4/95

nên 103/107>91/95

a: 3/5>1/2

b: 5/6<7/8

c: 8/9<7/6

d: 9/4<7/3

e: 8/12=2/3

f: 77/99=7/9

\(\dfrac{3}{5}>\dfrac{1}{2}\)

\(\dfrac{5}{6}< \dfrac{7}{8}\)

\(\dfrac{8}{9}< \dfrac{7}{6}\)

\(\dfrac{9}{4}< \dfrac{7}{3}\)

\(\dfrac{8}{12}=\dfrac{2}{3}\)

\(\dfrac{77}{99}=\dfrac{7}{9}\)

\(\dfrac{3}{5}>\dfrac{1}{2}\)

\(\dfrac{5}{6}< \dfrac{7}{8}\)

\(\dfrac{8}{9}< \dfrac{7}{6}\)

\(\dfrac{9}{4}< \dfrac{7}{3}\)

\(\dfrac{8}{12}=\dfrac{2}{3}\)

\(\dfrac{77}{99}=\dfrac{7}{9}\)

3/4 >2/4

\(\dfrac{6}{12}=\dfrac{6:3}{12:3}=\dfrac{2}{4}\)

\(\dfrac{3}{4}>\dfrac{2}{4}\)

3/4>2/4 nhá bạn 

a: 2/4=1/2=6/12

5/15=1/3=4/12

7/28=1/4=3/12

b: 6/8=3/4=15/20

25/125=1/5=4/20

1/4=5/20

c: 14/28=1/2=18/36

9/81=1/9=4/36

2/72=1/36

6/5>5/8 nhé

>

6/5>5/8

a)\(\dfrac{9}{12}=\dfrac{9:3}{12:3}=\dfrac{3}{4}\)

Vì 2x4<3x3

=>\(\dfrac{2}{3}< \dfrac{3}{4}\)

b)\(\dfrac{4}{8}=\dfrac{4:4}{8:4}=\dfrac{1}{2}\)

Vì 1x3<2x2

=>\(\dfrac{1}{2}< \dfrac{2}{3}\)

a) \(\dfrac{9}{12}\)=\(\dfrac{3}{4}\)

\(\dfrac{2}{3}=\dfrac{2.4}{3.4}\)=\(\dfrac{8}{12}\)

\(\dfrac{3}{4}=\dfrac{3.3}{4.3}=\dfrac{9}{12}\)

Vì \(\dfrac{9}{12}>\dfrac{8}{12}=>\)\(\dfrac{9}{12}>\dfrac{3}{4}\)

b) \(\dfrac{4}{8}=\dfrac{2}{4}\)

Ta có: \(\dfrac{2}{3}>\dfrac{2}{4}=>\dfrac{4}{8}< \dfrac{2}{3}\)

a)\(\dfrac{9}{12}=\dfrac{3}{4}\)

\(\dfrac{2}{3}=\dfrac{2\times4}{3\times4}=\dfrac{8}{12}\)

\(\Rightarrow\dfrac{8}{12}< \dfrac{9}{12}\) hay \(\dfrac{2}{3}< \dfrac{3}{4}\)

b)\(\dfrac{4}{8}=\dfrac{1}{2}\)

\(\dfrac{1}{2}=\dfrac{1\times3}{2\times3}=\dfrac{3}{6}\)

\(\dfrac{2}{3}=\dfrac{2\times2}{3\times2}=\dfrac{4}{6}\)

\(\Rightarrow\dfrac{3}{6}< \dfrac{4}{6}\) hay \(\dfrac{1}{2}< \dfrac{2}{3}\)

a: 2/3=10/15

4/5=12/15

mà 10/15<12/15

nên 2/3<4/5

b: 7/9=7/9

1/3=3/9

mà 7/9>3/9

nên 7/9>1/3

a) \(\dfrac{2}{3}< \dfrac{4}{5}\)

Vì \(\dfrac{10}{15}< \dfrac{12}{15}\)

b) \(\dfrac{7}{9}>\dfrac{1}{3}\) 

Vì \(\dfrac{14}{18}>\dfrac{6}{18}\)

a: Gọi phân số cần tìm có mẫu là x

Theo đề, ta có: 

\(\dfrac{3}{4}< \dfrac{19}{x}< \dfrac{5}{6}\)

\(\Leftrightarrow\dfrac{285}{380}< \dfrac{285}{x}< \dfrac{285}{342}\)

=>360>x>342

b: 3/4=9/12=18/24=27/36

5/6=10/12=20/24=30/36

=>Hai phân số cần tìm là 28/36; 29/36

28/36; 29/36