\(\frac{48}{96}=\frac{48:48}{96:48}=\frac{1}{2}\)

\(\frac{42}{98}=\frac{42:14}{98:14}=\frac{3}{7}\)

\(\frac{80}{240}=\frac{80:80}{240:80}=\frac{1}{3}\)

\(\frac{75}{100}=\frac{75:25}{100:25}=\frac{3}{4}\)

\(\frac{64}{720}=\frac{64:16}{720:16}=\frac{4}{45}\)

\(\frac{15}{120}=\frac{15:15}{120:15}=\frac{1}{8}\)

48/96=1/2

42/98=3/7

80/240=1/3

75/100=3/4

64/720=4/45

15/120=1/8

48/96=1/2

42/98=3/7

80/240=1/3

75/100=3/4

64/720=4/45

15/120=1/8

\(\dfrac{90}{120}=\dfrac{30.3}{30.4}=\dfrac{3}{4}\)

\(\dfrac{15}{25}=\dfrac{5.3}{5.5}=\dfrac{3}{5}\)

\(\dfrac{18}{45}=\dfrac{9.2}{9.5}=\dfrac{2}{5}\)

\(\dfrac{36}{64}=\dfrac{4.9}{4.16}=\dfrac{9}{16}\)

\(\dfrac{32}{72}=\dfrac{8.4}{8.9}=\dfrac{4}{9}\)

\(\dfrac{84}{49}=\dfrac{7.12}{7.7}=\dfrac{12}{7}\)

\(\dfrac{90}{120}=\dfrac{3}{4};\dfrac{15}{25}=\dfrac{3}{5};\dfrac{18}{45}=\dfrac{2}{5};\dfrac{36}{64}=\dfrac{9}{16};\dfrac{32}{72}=\dfrac{4}{9};\dfrac{84}{49}=\dfrac{12}{7}\)

\(\dfrac{3}{4},\dfrac{3}{5},\dfrac{2}{5},\dfrac{9}{16},\dfrac{4}{9},\dfrac{12}{7}\)

Ta rút gọn:

\(\frac{12}{15}=\frac{4}{5}=\frac{48}{60}\)

\(\frac{14}{-21}=\frac{-2}{3}=\frac{-40}{60}\)

\(\frac{-21}{-18}=\frac{21}{18}=\frac{7}{6}=\frac{70}{60}\)

\(\frac{-63}{108}\)= \(\frac{-7}{12}\)

\(\frac{-33}{-77}\)= \(\frac{3}{7}\)

\(\frac{-5}{10}\)=\(\frac{-1}{2}\)

\(\frac{14}{63}\)=\(\frac{2}{9}\)

\(\frac{-15}{25}\)=\(\frac{-3}{5}\)

\(\frac{-45}{18}\)=\(\frac{-5}{2}\)

\(\frac{12}{15}\)=\(\frac{4}{5}\)

\(\frac{20}{25}\)=\(\frac{4}{5}\)

\(\frac{31}{12}\):Là phân số tối giản

t.i.c.k nha                                           

Theo thứ tự : 5/6 ; 2/3 ; 2/3 ; 3/2 ; 2/3 ; 3/8 ; 3/1(hay là 3)

\(\dfrac{10}{12}=\dfrac{5}{6}\)        \(\dfrac{8}{12}=\dfrac{2}{3}\)        \(\dfrac{10}{15}=\dfrac{2}{3}\)        \(\dfrac{27}{18}=\dfrac{3}{2}\)        \(\dfrac{24}{36}=\dfrac{4}{6}=\dfrac{2}{3}\)

\(\dfrac{18}{48}=\dfrac{3}{8}\)        \(\dfrac{42}{14}=\dfrac{6}{2}=\dfrac{3}{1}\)

10/12 = 5/6 

8/12 = 2/3 

10/15 = 2/3 

27/18 = 3/2 

18/48 = 3/8 

42/14 = 3 

Tìm số thích hợp điền vào ô trống:1/   =18/27

a) \(\frac{15}{17}\)

Vì ƯCLN(15, 17)=1 nên phân số \(\frac{15}{17}\) đã tối giản

b) \(\frac{70}{105}\)

Ta có: 70 = 2.5.7;    105= 3.5.7

+ Thừa số nguyên tố chung là 5 và 7

+ Số mũ nhỏ nhất của 5 là 1, số mũ nhỏ nhất của 7 là 1 nên \(ƯCLN(70, 105) = 35 \ne 1\) nên phân số chưa tối giản. 

\(\frac{70}{105}=\frac{70:35}{105:35}=\frac{2}{3}\)

ƯCLN(2, 3)=1 nên \(\frac{70}{105}\) đã rút gọn về \(\frac{2}{3}\) tối giản.

https://olm.vn/hoi-dap/question/1037641.html

Rút gọn các phân số sau :

\(\frac{18}{30}=\frac{18\div6}{30\div6}=\frac{3}{5}\)

\(\frac{64}{80}=\frac{64\div16}{80\div16}=\frac{4}{5}\)

\(\frac{36}{27}=\frac{36\div9}{27\div9}=\frac{4}{3}\)

\(\frac{45}{35}=\frac{45\div5}{35\div5}=\frac{9}{7}\)

\(\frac{18}{30}=\frac{3}{5}\)

\(\frac{64}{80}=\frac{4}{5}\)

\(\frac{36}{27}=\frac{4}{3}\)

\(\frac{45}{35}=\frac{9}{7}\)

Ta có: \(\frac{{ - 18}}{{76}} = \frac{{ - 18:2}}{{76:2}} = \frac{{ - 9}}{{38}}\)

\(\frac{{125}}{{ - 375}} = \frac{{125:( - 125)}}{{ - 375:( - 125)}} = \frac{{ - 1}}{3}\)

\(-\dfrac{18}{76}=\dfrac{-9}{38};\dfrac{125}{-375}=-\dfrac{1}{3}\)