Because:
$\frac{1}{3}$ = $\frac{1 x 5}{3 x 5}$ = $\frac{5}{15}$
$\frac{2}{5}$ = $\frac{2 x 3}{5 x 3}$ = $\frac{6}{15}$
$\frac{5}{15}$ < $\frac{6}{15}$ so the oranges which mother gives her son is greater than the oranges which mother gives her daughter.
Bời vì:
$\frac{1}{3}$ = $\frac{1 x 5}{3 x 5}$ = $\frac{5}{15}$
$\frac{2}{5}$ = $\frac{2 x 3}{5 x 3}$ = $\frac{6}{15}$
$\frac{5}{15}$ < $\frac{6}{15}$ nên số cam mà mẹ cho em lớn hơn số cam mà mẹ cho chị.