\(\dfrac{2483-13}{4966-26}=\dfrac{2470}{4940}=\dfrac{2470:2470}{4940:2470}=\dfrac{1}{2}\)
\(\dfrac{2727-101}{7575+303}=\dfrac{2626}{7878}=\dfrac{2626:2626}{7878:2626}=\dfrac{1}{3}\)
\(\dfrac{2002}{2000.16-1970}=\dfrac{2002}{32000-1970}=\dfrac{2002}{30030}=\dfrac{2002:2002}{30030:2002}=\dfrac{1}{15}\)
\(\dfrac{1.2.3+2.4.6+4.8.12+7.4.21}{1.3.6+2.6.12+4.12.24+7.21.42}=\dfrac{6+48+384+588}{18+144+1152+6174}=\dfrac{54+972}{162+7326}\)
\(=\dfrac{1026}{7488}=\dfrac{1026:18}{7488:18}=\dfrac{57}{416}\)
Sau khi rút gọn ta có các phân số: \(\dfrac{1}{2};\dfrac{1}{3};\dfrac{1}{15};\dfrac{57}{416}\)
\(BCNN\left(2;3;15;416\right)=6240\)
\(\dfrac{1}{2}=\dfrac{1.3120}{2.3120}=\dfrac{3120}{6240}\)
\(\dfrac{1}{3}=\dfrac{1.2080}{3.2080}=\dfrac{2080}{6240}\)
\(\dfrac{1}{15}=\dfrac{1.416}{15.416}=\dfrac{416}{6240}\)
\(\dfrac{57}{416}=\dfrac{57.15}{416.15}=\dfrac{855}{6240}\)
