Rút gọn các phân số sau về phân số tối giản:
12/30 ................\(=\dfrac{12:6}{30:6}=\dfrac{2}{5}\)...........................................

20/45 ....................\(=\dfrac{20:5}{45:5}=\dfrac{4}{9}\)......................................

28/70.....................\(=\dfrac{28:14}{70:14}=\dfrac{2}{5}\).......................................

Rút gọn các phân số sau về phân số tối giản:
12/30 ..= 6/15........................................................

20/45 ..=4/9........................................................

28/70..=14/5..........................................................

34/51..=2/3..........................................................

215/300..=43/20.....................................................

1200/2010..=120/201.................................................

Bài 1 : Các số đó là : \(\frac{35}{60};\frac{46}{60}\)

Bài 2 :

\(\frac{12}{30}=\frac{12:6}{30:6}=\frac{2}{5}\); \(\frac{20}{45}=\frac{20:5}{45:5}=\frac{4}{9}\)

\(\frac{28}{70}=\frac{28:14}{70:14}=\frac{2}{5}\) ; \(\frac{34}{51}=\frac{34:17}{51:17}=\frac{2}{3}\)

Bài 1: 

7/12=35/60

23/30=46/60

Bài 2: 

12/30=2/5

20/45=4/9

28/70=2/5

34/51=2/3

k mình nha!

12/30 = 2/5

20/45 = 4/9

28/70 = 2/5

34/51 = 2/3

ht

TL

12/30=2/5

20/45=4/9

28/70=2/5

34/51=2/3

nha

HT

\(\frac{12}{30}=\frac{12:6}{30:6}=\frac{2}{5}\)

\(\frac{20}{45}=\frac{20:5}{45:5}=\frac{4}{9}\)

\(\frac{28}{70}=\frac{28:14}{70:14}=\frac{2}{5}\)

\(\frac{34}{51}=\frac{34:17}{51:17}=\frac{2}{3}\)

Hai phân số\(\frac{12}{30}\)và \(\frac{28}{70}\)có cùng tử số là 2 và mẫu số là 5 nhé

2/5

4/9

2/5

2/3

rút gọn phân số :
12/30 =2/5
20/45= 4/9
28/70=2/5
34/51 =2/3

12/30 = 2/5
20/45=  4/9
28/70= 2/5
34/51 = 2/3

\(\frac{12}{30}=\frac{2}{5}\)

\(\frac{20}{45}=\frac{4}{9}\)

\(\frac{28}{70}=\frac{2}{5}\)

\(\frac{34}{51}=\frac{2}{3}\)

\(\frac{12}{30}\)= \(\frac{12:6}{30:6}\)= \(\frac{2}{5}\)

\(\frac{20}{45}\)=\(\frac{20:5}{45:5}\)=\(\frac{4}{9}\)

\(\frac{28}{70}\)=\(\frac{28:7}{70:7}\)=\(\frac{4}{10}\)=\(\frac{4:2}{10:2}\)=\(\frac{2}{5}\)

\(\frac{34}{51}\)=\(\frac{34:14}{51:14}\)=\(\frac{34:17}{51:17}\)= \(\frac{2}{3}\)

\(\frac{12}{30}=\frac{12:6}{30:6}=\frac{2}{5}\)

\(\frac{20}{45}=\frac{20:5}{45:5}=\frac{4}{9}\)

\(\frac{28}{70}=\frac{28:14}{70:14}=\frac{2}{5}\)

\(\frac{34}{51}=\frac{34:17}{51:17}=\frac{2}{3}\)

\(\frac{12}{30}=\frac{12:6}{30:6}=\frac{2}{5}\)

\(\frac{20}{45}=\frac{20:5}{45:5}=\frac{4}{9}\)

\(\frac{28}{70}=\frac{28:14}{70:14}=\frac{2}{5}\)

\(\frac{34}{51}=\frac{34:17}{51:17}=\frac{2}{3}\)

ủng hộ mình nha

12/30 = 12:6/30:6 = 2/5

20/45 = 20:5/45:5 = 4/9

28/70 = 28:14/70:14 = 2/5

34/51 = 34:17/51:17 = 2/3

\(\dfrac{14}{28}=\dfrac{14:14}{28:14}=\dfrac{1}{2}\)

\(\dfrac{33}{99}=\dfrac{33:33}{99:33}=\dfrac{1}{3}\)

\(\dfrac{12}{80}=\dfrac{12:4}{80:4}=\dfrac{3}{20}\)

\(\dfrac{50}{150}=\dfrac{50:50}{150:50}=\dfrac{1}{3}\)

\(\dfrac{45}{9}=\dfrac{45:9}{9:9}=5\)

\(\dfrac{81}{72}=\dfrac{81:9}{72:9}=\dfrac{9}{8}\)

\(\dfrac{34}{68}=\dfrac{34:34}{68:34}=\dfrac{1}{2}\)

14/28=1/2

33/99=1/3

12/80=3/20

50/150=1/3

45/9=5

81/72=9/8

34/68=1/2

\(\dfrac{14}{28}=\dfrac{1}{2};\dfrac{33}{99}=\dfrac{11}{33};\dfrac{12}{80}=\dfrac{3}{20};\dfrac{50}{150}=\dfrac{1}{3};\dfrac{45}{9}=5;\dfrac{81}{72}=\dfrac{9}{8};\dfrac{34}{68}=\dfrac{1}{2}\)

c ) − 5 15 = ( − 5 ) : 5 15 : 5 = − 1 2 d ) − 12 − 24 = ( − 12 ) : ( − 12 ) ( − 24 ) : ( − 12 ) = 1 2

e ) 54 270 = 54 : 54 270 : 54 = 1 5 f ) − 12 − 28 = ( − 12 ) : ( − 4 ) ( − 28 ) : ( − 4 ) = 3 7

g ) − 18 − 27 = ( − 18 ) : ( − 9 ) ( − 27 ) : ( − 9 ) = 2 3 h ) 45 − 24 = 45 : ( − 3 ) ( − 24 ) : ( − 3 ) = − 15 8