Rút gọn:

\(\frac{18}{30}=\frac{18:6}{30:6}=\frac{3}{5}\)

\(\frac{36}{27}=\frac{36:9}{27:9}=\frac{4}{3}\)

\(\frac{64}{80}=\frac{64:16}{80:16}=\frac{4}{5}\)

\(\frac{45}{35}=\frac{45:5}{35:5}=\frac{9}{7}\)

bài dễ tự làm đi 

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

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

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

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

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

Rút gọn các phân số sau :

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

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

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

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

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

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

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

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

\(\frac{36}{64}=\frac{36:4}{64:4}=\frac{9}{16}\)

            \(~~~Hok\)tốt\(~~~\)

9/16

let's be friends

9/16 nha

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

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

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

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

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

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

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

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

Đặt \(A=\frac{1}{4}+\frac{1}{16}+\frac{1}{36}+\frac{1}{64}+\frac{1}{100}+\frac{1}{144}+\frac{1}{196}\)

\(\Rightarrow A=\frac{1}{2^2}+\frac{1}{4^2}+\frac{1}{6^2}+\frac{1}{8^2}+\frac{1}{10^2}+\frac{1}{12^2}+\frac{1}{14^2}\)

\(\Rightarrow\frac{1}{2^2}.A=\frac{1}{2^2}.\left(\frac{1}{2^2}+\frac{1}{4^2}+\frac{1}{6^2}+\frac{1}{8^2}+\frac{1}{10^2}+\frac{1}{12^2}+\frac{1}{14^2}\right)\)

\(\Rightarrow\frac{1}{4}.A=\frac{1}{4^2}+\frac{1}{6^2}+\frac{1}{8^2}+\frac{1}{10^2}+\frac{1}{12^2}+\frac{1}{14^2}+\frac{1}{16^2}\)

\(\Rightarrow A-\frac{1}{4}.A=\left(\frac{1}{2^2}+\frac{1}{4^2}+\frac{1}{6^2}+\frac{1}{8^2}+\frac{1}{10^2}+\frac{1}{12^2}+\frac{1}{14^2}\right)-\left(\frac{1}{4^2}+\frac{1}{6^2}+\frac{1}{8^2}+\frac{1}{10^2}+\frac{1}{12^2}+\frac{1}{14^2}+\frac{1}{16^2}\right)\)

\(\Rightarrow\frac{3}{4}.A=\frac{1}{2^2}-\frac{1}{16^2}=\frac{1}{4}-\frac{1}{256}=\frac{63}{256}\)

\(\Rightarrow A=\frac{63}{256}:\frac{3}{4}=\frac{21}{64}\)

K rút họn đc đâu bạn. Bạn muốn chứng minh tổng trên bé hơn hoặc lớn hơn số nào thì đc

  90 /120 = 9/12 = 3/4 

36 / 64 = 18/32= 9 /16 

90/120=3/4

36/64=9/16

ta thấy 90/120 cùng chia hết cho 3 nên phân số rút gọn là 30/40

ta thấy phân số 36/64 cùng chia hết cho 4 nên phân số rút gọn là 9/16

3/5

2/3

9/16

ngu dốt

\(\frac{48}{64}\)= \(\frac{24}{32}\)= \(\frac{12}{16}\)= \(\frac{6}{8}\)=\(\frac{3}{4}\)

\(\frac{48}{64}\)=\(\frac{3}{4}\) ủng hộ mk nha!!! ##@@.vn

\(\frac{48}{64}\)= \(\frac{3}{4}\)

chúc học tốthà phương lenguyen