The oranges are identical and the children are distinct.
Each child must receive at least one orange.
The number of ways to distribute $n$ identical objects into $r$ distinct
groups, with no group empty, is given by:
\[
\binom{n-1}{r-1}
\]
Here,
\[
n = 16, \quad r = 4
\]
\[
\text{Number of ways} = \binom{15}{3}
\]
\[
= \frac{15 \times 14 \times 13}{3 \times 2 \times 1}
= 5 \times 7 \times 13
= 455
\]
\[
\therefore \text{the required number of ways is } \boxed{455}.
\]