`25/50=(25:25)/(50:25)=1/2`
`15/120=(15:15)/(120:15)=1/8`
`64/720=(64:16)/(720:16)=4/45`
`5/25=(5:5)/(25:5)=1/2`
`6/9=(6:3)/(9:3)=2/3`
`48/96=(48:48)/(96:48)=1/2`
`42/98=(42:14)/(98:14)= 3/7`
`18/30=(18:6)/(30:6)=3/5`
`80/240=(80:80)/(240:80)=1/3`
Bài 3:
\(\dfrac{25}{50}=\dfrac{25:25}{50:25}=\dfrac{1}{2}\)
\(\dfrac{15}{120}=\dfrac{15:15}{120:15}=\dfrac{1}{8}\)
\(\dfrac{64}{720}=\dfrac{64:16}{720:16}=\dfrac{4}{45}\)
\(\dfrac{5}{25}=\dfrac{5:5}{25:5}=\dfrac{1}{5}\)
\(\dfrac{6}{9}=\dfrac{6:3}{9:3}=\dfrac{2}{3}\)
\(\dfrac{48}{96}=\dfrac{48:48}{96:96}=\dfrac{1}{2}\)
\(\dfrac{42}{98}=\dfrac{42:14}{98:14}=\dfrac{3}{7}\)
\(\dfrac{18}{30}=\dfrac{18:6}{30:6}=\dfrac{3}{5}\)
\(\dfrac{80}{240}=\dfrac{80:80}{240:80}=\dfrac{1}{3}\)
2550=25:2550:25=122550=25:2550:25=12
15120=15:15120:15=1815120=15:15120:15=18
64720=64:16720:16=44564720=64:16720:16=445
525=5:525:5=12525=5:525:5=12
69=6:39:3=2369=6:39:3=23
4896=48:4896:48=124896=48:4896:48=12
4298=42:1498:14=374298=42:1498:14=37
1830=18:630:6=351830=18:630:6=35
80240=80:80240:80=