Answer
$3.25×10^{-3}$
Work Step by Step
To convert a number from standard notation to scientific notation, we must move the decimal to the left or to the right, counting the number of places, until the number is between $1$ and $10$, and multiply by a power of $10$. If the number is less than $1$, and we moved the decimal to the right, the power of $10$ is the negative number of places we moved the decimal point. If the number is greater than $1$, and we moved the decimal to the left, the power of $10$ is the positive number of places we moved the decimal point.
For the number $0.00325$, we move the decimal point $3$ places to the right, giving us $3.25$, with the power of $10$ being $-3$.
This gives us $3.25×10^{-3}$.