Bài `4`
`24/60= 6/15=2/5=8/20`
`42/54=7/9=14/18=21/27`
Bài `5`
`a,` \(\dfrac{4\times5\times3}{3\times7\times4}=\dfrac{5}{7}\)
`b,` \(\dfrac{7\times9\times11}{11\times7\times5}=\dfrac{9}{5}\)
Phần `1`
\(\dfrac{4}{14}\) tối giản
\(\dfrac{12}{15}=\dfrac{12:3}{15:3}=\dfrac{4}{5}\)
\(\dfrac{18}{54}=\dfrac{18:18}{54:18}=\dfrac{1}{3}\)
\(\dfrac{36}{45}=\dfrac{36:9}{45:9}=\dfrac{4}{5}\)
\(\dfrac{50}{70}=\dfrac{50:10}{70:10}=\dfrac{5}{7}\)
\(\dfrac{24}{120}=\dfrac{24:24}{120:24}=\dfrac{1}{2}\)
\(\dfrac{24}{36}=\dfrac{24:12}{36:12}=\dfrac{2}{3}\)
\(\dfrac{132}{55}=\dfrac{132:11}{55:11}=\dfrac{12}{5}\)
`2`
`a,`các phân số tối giản là : \(\dfrac{8}{11};\dfrac{4}{7}\)
`b,` phân số bằng \(\dfrac{3}{4}\) : \(\dfrac{45}{60};\dfrac{12}{16}\)
`3`
các phân số bằng nhau : \(\dfrac{18}{33}=\dfrac{6}{11}\) ; \(\dfrac{5}{7}=\dfrac{20}{28}\) ; \(\dfrac{8}{10}=\dfrac{12}{15}\) ; \(\dfrac{14}{21}=\dfrac{24}{36}\)
