Use a calculator to evaluate the expression.
\[
{ }_{18} \mathrm{P}_{8}
\]
\[
{ }_{18} P_{8}=
\]
(Use scientific notation. Use the multiplication symbol in the math palette as needed.)

Step 1 ：The given expression is a permutation, which is a way of arranging items where the order is important. In this case, we are asked to find the number of ways to arrange 8 items out of 18.

Step 2 ：The formula for permutation is: \(P(n, r) = \frac{n!}{(n-r)!}\) where n is the total number of items, r is the number of items to choose, and '!' denotes factorial, which is the product of all positive integers up to that number.

Step 3 ：So, we need to calculate the factorial of 18, the factorial of (18-8), and then divide the first by the second.

Step 4 ：Let's calculate: n = 18, r = 8, factorial_n = 6402373705728000, factorial_n_r = 3628800

Step 5 ：Then, calculate the permutation: permutation = 1764322560.0

Step 6 ：Final Answer: The permutation of 18 items taken 8 at a time is \(\boxed{1764322560}\).