\(2\dfrac{2}{3}=\dfrac{2\times3+2}{3}=\dfrac{8}{3}\)

\(3\dfrac{2}{1}=\dfrac{3\times1+2}{1}=\dfrac{5}{1}\)

\(\dfrac{8}{3}:\dfrac{5}{1}=\dfrac{8}{3}\times\dfrac{1}{5}=\dfrac{8}{15}\)

Chuyển hỗn số thành phân số :

\(2\dfrac{2}{3}=\dfrac{2x3+2}{3}=\dfrac{8}{3}\)

\(3\dfrac{2}{1}=\dfrac{3x1+2}{3}=\dfrac{5}{3}\)

Vậy nên :

\(2\dfrac{2}{3}:3\dfrac{2}{1}=\dfrac{8}{3}:\dfrac{5}{3}=\dfrac{8}{3}x\dfrac{3}{5}=\dfrac{24}{15}=\dfrac{8}{5}\)

\(3\dfrac{2}{1}=\dfrac{3x1+2}{1}=\dfrac{5}{1}\)

\(\dfrac{8}{3}x\dfrac{1}{5}=\dfrac{8}{15}\)

\(1\dfrac{1}{5}+1\dfrac{2}{4}=\dfrac{6}{5}+\dfrac{6}{4}=\dfrac{24}{20}+\dfrac{30}{20}=\dfrac{54}{40}\)

Cách chuyển hỗn số thành phân số :

\(1\dfrac{1}{5}=\dfrac{1x5+1}{5}=\dfrac{6}{5}\)

\(1\dfrac{2}{4}=\dfrac{1x4+2}{4}\dfrac{6}{4}\)

\(1\dfrac{1}{5}+1\dfrac{2}{4}=\dfrac{6}{5}+\dfrac{3}{2}=\dfrac{6\times2}{5\times2}+\dfrac{3\times5}{2\times5}=\dfrac{12}{10}+\dfrac{15}{10}=\dfrac{12+15}{10}=\dfrac{27}{10}.\)

\(2\dfrac{3}{4}=\dfrac{2\times4+3}{4}=\dfrac{11}{4}\\ 3\dfrac{4}{5}=\dfrac{3\times5+4}{5}=\dfrac{19}{5}\\ 4\dfrac{3}{5}=\dfrac{4\times5+3}{5}=\dfrac{23}{5}\\ 11\dfrac{12}{13}=\dfrac{11\times13+12}{13}=\dfrac{155}{13}\\ 12\dfrac{11}{13}=\dfrac{12\times13+11}{13}=\dfrac{167}{13}\\ 3\dfrac{3}{5}=\dfrac{3\times5+3}{5}=\dfrac{18}{5}\)

2\(\dfrac{3}{4}\)=\(\dfrac{11}{4}\)

3\(\dfrac{4}{5}\)=\(\dfrac{19}{5}\)

4\(\dfrac{3}{5}\)=\(\dfrac{23}{5}\)

11\(\dfrac{12}{13}\)=\(\dfrac{155}{13}\)

12\(\dfrac{11}{13}\)=\(\dfrac{167}{13}\)

3\(\dfrac{3}{5}\)=\(\dfrac{18}{5}\).

\(\dfrac{54}{10}=5,4\)

\(4\dfrac{78}{1000}=4+\dfrac{78}{1000}=4+0,078=4,078\)

\(18\dfrac{4}{100}=18+\dfrac{4}{100}=18+0,04=18,04\)

\(\dfrac{1990}{10000}=\dfrac{199}{1000}=0,199\)

\(\dfrac{54}{10}=\dfrac{27}{5}=5,4\)

\(4\dfrac{78}{1000}=\dfrac{39}{125}=0,312\)

\(18\dfrac{4}{100}=\dfrac{18}{25}=0,72\)

\(\dfrac{1990}{10000}=\dfrac{199}{1000}=0,199\)

5410=5,41054​=5,4

4781000=4+781000=4+0,078=4,0784100078​=4+100078​=4+0,078=4,078

184100=18+4100=18+0,04=18,04181004​=18+1004​=18+0,04=18,04

199010000=1991000=0,199100001990​=1000199​=0,199

đây nè

5,67

25\(\dfrac{567}{100}\) = \(\dfrac{25\times100+567}{100}\) = \(\dfrac{3067}{100}\) 

5,67

`12/5 =` `2``2/5`

``37/6 =` `6``1/6`

`108/9 =` `12``0/9`

2020/2019 x 2019/2018 x 2018/2017 x....................3/2
= 2020/2
= 1010 

\(A=1\dfrac{1}{2019}\times1\dfrac{1}{2018}\times1\dfrac{1}{2017}\times...\times1\dfrac{1}{2}\)

\(=\dfrac{2020}{2019}\times\dfrac{2019}{2018}\times\dfrac{2018}{2017}\times...\times\dfrac{3}{2}\)

\(=\dfrac{2020}{2}\)

\(=1010\)

Ta co

3/7=24/42

3/8=18/48

+.6 P/S do la :

18/43,18/44,18/45,18/46,18/47

=2x8+7      /8

=23/8

cich cho minh di