4. Mother has a few oranges. She gives her daughter$\frac{1}{3}$ of the oranges and gives her...

Since $rac{6}{15}$ is greater than $rac{5}{15}$, the son receives more oranges from their mother.

Therefore, the daughter receives $rac{5}{15}$ of the oranges and the son receives $rac{6}{15}$ of the oranges.

Once we have a common denominator, we can convert $rac{1}{3}$ and $rac{2}{5}$ to have the same denominator. $rac{1}{3}$ becomes $rac{5}{15}$ and $rac{2}{5}$ becomes $rac{6}{15}$.

The common denominator for $rac{1}{3}$ and $rac{2}{5}$ is 15 (because 3 and 5 both divide evenly into 15).

To compare the amount of oranges each child receives, we need to find a common denominator for $rac{1}{3}$ and $rac{2}{5}$.