$\frac{2}{8}$ + $\frac{5}{6}$ = $\frac{6}{24}$ + $\frac{20}{24}$ = $\frac{26}{24}$ = $\frac{13}{12}$
$\frac{1}{4}$ + $\frac{6}{30}$ = $\frac{15}{60}$ + $\frac{12}{60}$ = $\frac{27}{60}$ = $\frac{9}{20}$
$\frac{1}{8}$ + $\frac{12}{6}$ = $\frac{3}{24}$ + $\frac{48}{24}$ = $\frac{51}{24}$ = $\frac{17}{8}$
$\frac{12}{18}$ + $\frac{12}{42}$ = $\frac{2}{3}$ + $\frac{2}{7}$ = $\frac{14}{21}$ + $\frac{6}{21}$ = $\frac{20}{21}$
Học tốt ^^