Solve the Multiplication Problem: 1×1000 = ?

To solve this problem, we need to multiply $1$ by $1000$. According to the identity property of multiplication, any number multiplied by $1$ remains unchanged.

Let's apply this principle:

$1 \times 1000 = 1000$

This property informs us that the product of $1 \times 1000$ is simply the number $1000$.

Therefore, the solution to the problem is $1000$.

Checking the possible answer choices, we find that choice $1000$ is the correct answer.