3/5

2/3

9/16

ngu dốt

\(\dfrac{25}{30}=\dfrac{5}{6}\)

\(\dfrac{9}{15}=\dfrac{3}{5}\)

\(\dfrac{10}{12}=\dfrac{5}{6}\)

\(\dfrac{6}{10}=\dfrac{3}{5}\)

Bạn nhìn theo phần rút gọn tui gửi mà so sánh các phân số khác nhek

\(\dfrac{25}{30}=\dfrac{5}{6}\)

\(\dfrac{10}{12}=\dfrac{5}{6}\)

\(\dfrac{6}{10}=\dfrac{3}{5}\)

\(\dfrac{25}{30}=\dfrac{5}{7};\dfrac{9}{15}=\dfrac{3}{5};\dfrac{6}{10}=\dfrac{3}{5};\dfrac{10}{12}=\dfrac{5}{6}\)

tự xem cái nào giống

a) \(\dfrac{3}{5};\dfrac{5}{6}\) : phân số tối giản
\(\dfrac{25}{30}=\dfrac{25:5}{30:5}=\dfrac{5}{6}\)
\(\dfrac{9}{15}=\dfrac{9:3}{15:3}=\dfrac{3}{5}\)
\(\dfrac{10}{12}=\dfrac{10:2}{12:2}=\dfrac{5}{6}\)
\(\dfrac{6}{10}=\dfrac{6:2}{10:2}=\dfrac{3}{5}\)
b) \(\dfrac{3}{5}=\dfrac{9}{15}=\dfrac{6}{10}\) ; \(\dfrac{5}{6}=\dfrac{25}{30}=\dfrac{10}{12}\)

Giải:

a) \(\dfrac{5^3.90.4^3}{25^2.3^2.2^{13}}\) 

\(=\dfrac{5^3.5.3^2.2.\left(2^2\right)^3}{\left(5^2\right)^2.3^2.2^{13}}\) 

\(=\dfrac{5^4.3^2.2.2^6}{5^4.3^2.2^{13}}\) 

\(=\dfrac{5^4.3^2.2^7}{5^4.3^2.2^{13}}\) 

\(=\dfrac{1}{2^6}=\dfrac{1}{64}\) 

b) \(\dfrac{15^2.16^4-15^3.16^3}{12^2.20^3-20^2.12^3}\) 

\(=\dfrac{15^2.16^3.16-15^2.16^3.15}{12^2.20^2.20-20^2.12^2.12}\) 

\(=\dfrac{15^2.16^3.\left(16-15\right)}{12^2.20^2.\left(20-12\right)}\) 

\(=\dfrac{\left(3.5\right)^2.\left(2^4\right)^3.1}{\left(3.2^2\right)^2.\left(2^2.5\right)^2.8}\) 

\(=\dfrac{3^2.5^2.2^{12}}{3^2.\left(2^2\right)^2.\left(2^2\right)^2.5^2.2^3}\) 

\(=\dfrac{3^2.5^2.2^{12}}{3^2.5^2.2^4.2^4.2^3}\) 

\(=\dfrac{3^2.5^2.2^{12}}{3^2.5^2.2^{11}}\) 

\(=2\) 

c) \(\dfrac{2.3+4.6+14.21}{3.5+6.10+21.35}\) 

\(=\dfrac{2.3+2.3.2.2+2.3.7.7}{3.5+3.5.2.2+3.5.7.7}\) 

\(=\dfrac{2.3+2.3.4+2.3.49}{3.5+3.5.4+3.5.49}\) 

\(=\dfrac{2.3.\left(1+4+49\right)}{3.5.\left(1+4+49\right)}\) 

\(=\dfrac{2.3}{3.5}\) 

\(=\dfrac{2}{5}\) 

Chúc bạn học tốt!

=1/2+1/3=5/6

\(\dfrac{1}{2}+\dfrac{1}{3}=\dfrac{5}{6}\)

\(=\dfrac{1}{2}+\dfrac{1}{3}=\dfrac{5}{6}emnhé\)

Phân số \(\dfrac{{11}}{{23}}\) là phân số tối giản vì ƯCLN (11,23) = 1.

Phân số \(\dfrac{{ - 24}}{{15}}\) chưa tối giản.

\(\dfrac{{ - 24}}{{15}}= \dfrac{{ - 24:3}}{{15:3}} = \dfrac{{ - 8}}{5}\)

a) \(\dfrac{56}{42}=\dfrac{28}{21}=\dfrac{4}{3}\)

\(\dfrac{16}{24}=\dfrac{2}{3}=\dfrac{8}{12}=\dfrac{40}{60}\)

b) \(\dfrac{40}{25}=\dfrac{8}{5}\)

\(\dfrac{63}{81}=\dfrac{7}{9}\)

\(\dfrac{36}{60}=\dfrac{3}{5}\)

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

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

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

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

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

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

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

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

a)

Phân số đã tối giản: \(\dfrac{2}{3}\); \(\dfrac{5}{17}\);\(\dfrac{1}{10}\)Phân số nào chưa tối giản: \(\dfrac{9}{21}\); \(\dfrac{10}{15}\); \(\dfrac{7}{14}\) 

b) Rút gọn

\(\dfrac{21}{9}\) = \(\dfrac{7}{3}\)
\(\dfrac{10}{15}\) = \(\dfrac{2}{3}\)
\(\dfrac{7}{14}\) = \(\dfrac{1}{2}\)

a) Phân số tối giản là: \(\dfrac{2}{3};\dfrac{5}{17};\dfrac{1}{10}.\)

 Phân số chưa tối giản là: \(\dfrac{9}{21};\dfrac{10}{15};\dfrac{7}{14}\)

b)

 \(\dfrac{10}{15}=\dfrac{10:5}{15:5}=\dfrac{2}{3}\\ \dfrac{7}{14}=\dfrac{7:7}{14:7}=\dfrac{1}{2}\)