user
Return your final response within \boxed{}. Given that \(1 \leq x, y, z \leq 6\), how many cases are there in which the product of natural numbers \(x, y, z\) is divisible by 10?
assistant
<|begin_of_thought|>

Deep Thought is thinking for 7.5 million years.

<|end_of_thought|>

<|begin_of_solution|>

Given the constraints \(1 \leq x, y, z \leq 6\), we are to find the number of natural number combinations \((x, y, z)\) such that their product can be divided exactly by 10. 

To begin, we observe:
1. The total number of combinations of \(x, y, z\) is \(6^3\):
   \[
   6^3 = 216
   \]

2. To be divisible by 10, the product \(xyz\) must include both a factor of 2 and a factor of 5. Therefore, we need to evaluate the ways we can count combinations of \(x, y, z\) that miss these factors.

3. Consider the cases where \(x, y, z\) do not include factors of 2. The numbers within the range that are not multiples of 2 are \{1, 3, 5\}. The number of combinations in this case is:
   \[
   3^3 = 27
   \]

4. Next, consider the cases where \(x, y, z\) do not include factors of 5. The numbers within the range that are not multiples of 5 are \{1, 2, 3, 4, 6\}. The number of combinations in this case is:
   \[
   5^3 = 125
   \]

5. Now consider the cases where \(x, y, z\) include neither factors of 2 nor factors of 5. The only valid numbers in the range are then \{1, 3\}. The number of combinations in this case is:
   \[
   2^3 = 8
   \]

6. Using the principle of inclusion-exclusion, we can calculate the number of combinations where \(xyz\) is not divisible by 10:
   \[
   |A \cup B| = |A| + |B| - |A \cap B|
   \]
   where \(A\) is the set of combinations not including any multiples of 2 (27 in total) and \(B\) is the set not including any multiples of 5 (125 in total), and \(|A \cap B| = 8\):

   \[
   |A \cup B| = 27 + 125 - 8 = 144
   \]

7. Therefore, the number of combinations where \(xyz\) is divisible by 10 is:
   \[
   6^3 - |A \cup B| = 216 - 144 = 72
   \]

Conclusively, the number of natural number combinations \(x, y, z\) such that their product is divisible by 10 is:
\[
\boxed{72}
\]

<|end_of_solution|>