5. (5 points) When 4 identical small cubes (the six faces of the small cubes are marked with the numbers $1, 2, 3, 4, 5$, and $6$) are thrown simultaneously, the number of possible sums of the 4 numbers on the top faces is $\qquad$ kinds.
5. (5 points) When 4 identical small cubes (the six faces of the small cubes are marked with the numbers $1, 2, 3, 4, 5$, and $6$) are rolled, the sum of the 4 numbers on the top faces has $\qquad$ kinds.

【Solution】According to the analysis,
the minimum sum of the 4 numbers on the top faces is: $1 \times 4=4$, and the maximum sum is $6 \times 4=24$,
$24-4+1=21$ (kinds)
Answer: The sum of the 4 numbers on the top faces has 21 kinds.
Therefore, the answer is: 21.