= 11/2 nha bn

11/2 bạn nha tk và kb với mk đi

\(\frac{1}{5}=\frac{1.3}{5.3}=\frac{3}{15}\)

\(\frac{-10}{55}=\frac{-10\div5}{55\div5}=\frac{-2}{11}\)

Vậy ba cặp số phân số bằng nhau sau khi sử dụng tính chất cơ bản

2 .

\(\frac{-12}{-3}=\frac{-12:3}{-3:3}=\frac{-4}{-1};\frac{7}{-35}=\frac{7:7}{-35:7}=\frac{1}{-5};\frac{-9}{27}=\frac{-9:9}{27:9}=\frac{-1}{3}\)

3 .

\(15min=\frac{1}{4}\)giờ

\(90min=\frac{3}{2}\)giờ

\(\dfrac{19}{143}\times\dfrac{11}{57}=\dfrac{1}{39}\)

\(\dfrac{12}{25}\times\dfrac{39}{17}\times\dfrac{51}{52}=\dfrac{27}{25}\)

a. 3

b. 122/99

c.110

d.1

đ.120

e13/17

a.3

b. 1,(23) = 1 + 0,(23) = 1 + 23 . 0,(01) = 1+ 23 . 1/99 = 1 + 23/99 = 122/99

c.110

\(0,75=\dfrac{75}{100}=\dfrac{75:25}{100:25}=\dfrac{3}{4}\\ 0,8=\dfrac{8}{10}=\dfrac{8:2}{10:2}=\dfrac{4}{5}\\ 2,15=\dfrac{215}{100}=\dfrac{215:5}{100:5}=\dfrac{43}{20}\)

A) \(0,75=\dfrac{75}{100}=\dfrac{75:25}{100:25}=\dfrac{3}{4}\)

B) \(0,8=\dfrac{8}{10}=\dfrac{8:2}{10:2}=\dfrac{4}{5}\)

C) \(2,15=\dfrac{215}{100}=\dfrac{215:5}{100:5}=\dfrac{43}{20}\)

a) Các phân số tối giản là: \(\dfrac{5}{9};\dfrac{7}{19}\)

b) Các phân số chưa tối giản là: \(\dfrac{26}{24};\dfrac{11}{22};\dfrac{21}{36}\)

Rút gọn: \(\left\{{}\begin{matrix}\dfrac{26}{24}=\dfrac{26:2}{24:2}=\dfrac{13}{12}\\\dfrac{11}{22}=\dfrac{11:11}{22:11}=\dfrac{1}{2}\\\dfrac{21}{36}=\dfrac{21:3}{36:3}=\dfrac{7}{12}\end{matrix}\right.\)

\(a,\dfrac{5}{9};\dfrac{7}{19}\\ b,\dfrac{26}{24}=\dfrac{13}{12};\dfrac{11}{22}=\dfrac{1}{2};\dfrac{21}{36}=\dfrac{7}{12}\)

\(x:\dfrac{1}{8}=\dfrac{6}{11}\\ x=\dfrac{6}{11}\times\dfrac{1}{8}\\ x=\dfrac{3}{44}\)

3/44