3/5

2/3

9/16

ngu dốt

a: \(=\dfrac{13\cdot\left(9-2\right)}{13}=7\)

b: \(=\dfrac{14\left(3-8\right)}{7\left(1+3\cdot3\right)}=2\cdot\dfrac{-5}{10}=-1\)

c: \(=\dfrac{54-72}{36}=\dfrac{-18}{36}=-\dfrac{1}{2}\)

d: \(=\dfrac{5^3}{10^2\cdot5}=\dfrac{5^2}{100}=\dfrac{1}{4}\)

\(\dfrac{15}{25}=\dfrac{15:5}{25:5}=\dfrac{3}{5}\\ \dfrac{24}{28}=\dfrac{24:4}{28:4}=\dfrac{6}{7}\\ \dfrac{18}{33}=\dfrac{18:3}{33:3}=\dfrac{6}{11}\\ \dfrac{12}{36}=\dfrac{12:12}{36:12}=\dfrac{1}{3}.\)

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

\(\dfrac{24}{28}=\dfrac{6}{7}\)

\(\dfrac{18}{33}=\dfrac{6}{11}\)

\(\dfrac{12}{36}=\dfrac{1}{3}\)

\(\dfrac{15}{25}=\dfrac{15:5}{25:5}=\dfrac{3}{5}\\ \dfrac{24}{28}=\dfrac{24:4}{28:4}=\dfrac{6}{7}\\ \dfrac{18}{33}=\dfrac{18:3}{33:3}=\dfrac{6}{11}\\ \dfrac{12}{36}=\dfrac{12:12}{36:12}=\dfrac{1}{3}\)

Bài 1:

Bài 2:

Các bạn giúp mình câu này nha! 

\(\dfrac{3}{6}=\dfrac{3:3}{6:3}=\dfrac{1}{2}\\ \dfrac{18}{24}=\dfrac{18:6}{24:6}=\dfrac{3}{4}\\ \dfrac{5}{35}=\dfrac{5:5}{35:5}=\dfrac{1}{7}\\ \dfrac{40}{90}=\dfrac{40:10}{90:10}=\dfrac{4}{9}\\ \dfrac{75}{30}=\dfrac{75:15}{30:15}=\dfrac{5}{2}\)

\(\dfrac{3}{6}=\dfrac{3:3}{6:3}=\dfrac{1}{2}\\ \dfrac{18}{24}=\dfrac{18:6}{24:6}=\dfrac{3}{4}\\ \dfrac{5}{35}=\dfrac{5:5}{35:5}=\dfrac{1}{7}\\ \dfrac{40}{90}=\dfrac{40:10}{90:10}=\dfrac{4}{9}\\ \dfrac{75}{30}=\dfrac{75:15}{30:15}=\dfrac{5}{2}\)

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

\(\dfrac{18}{24}=\dfrac{18:6}{24:6}=\dfrac{3}{4}\)

\(\dfrac{5}{35}=\dfrac{5:5}{35:5}=\dfrac{1}{7}\)

\(\dfrac{40}{90}=\dfrac{40:10}{90:10}=\dfrac{4}{9}\)

\(\dfrac{75}{30}=\dfrac{75:15}{30:15}=\dfrac{5}{2}\)

a) \(\dfrac{8}{16}=\dfrac{8:8}{16:8}=\dfrac{1}{2}\)

b) \(\dfrac{10}{30}=\dfrac{10:10}{30:10}=\dfrac{1}{3}\)

c) \(\dfrac{24}{18}=\dfrac{24:6}{18:6}=\dfrac{4}{3}\)

d) \(\dfrac{20}{28}=\dfrac{20:4}{28:4}=\dfrac{5}{7}\)

a) Số:

\(\dfrac{12}{18}\) = \(\dfrac{6}{9}\)  = \(\dfrac{2}{3}\) 

b) Rút gọn các phân số:
\(\dfrac{12}{48}\) = \(\dfrac{1}{4}\)

\(\dfrac{80}{100}\)= \(\dfrac{4}{5}\) 

\(\dfrac{75}{125}\) = \(\dfrac{3}{5}\) 

a) Cách rút gọn của Thảo nhanh hơn còn của Hiếu thì lâu hơn vì phải làm nhiều bước

b) Sử dụng cách của Hiếu:

\(\dfrac{30}{60}=\dfrac{30:10}{60:10}=\dfrac{3}{6}=\dfrac{3:3}{6:3}=\dfrac{1}{2}\)

Sử dụng cách của Thảo:

\(\dfrac{30}{60}=\dfrac{30:30}{60:30}=\dfrac{1}{2}\)