Typical normal distribution tables give values of $\Phi(x) = P\{X \leq x\}$
for nonnegative
values of $x$ where $X$ is a standard normal random variable, usually for
$x$ in the range from $0$ to $3.5$. Now, for any normal random variable $Y$
with mean $\mu$ and standard deviation $\sigma$,
$$ P\{Y \leq y\} = \Phi\left(\frac{y-\mu}{\sigma}\right)$$
Remember the argument on the right as distance of $y$ from the mean
$\mu$ measured in units of the standard deviation $\sigma$.
More generally,
$$P\{y_1 \leq Y \leq y_2\} = P\{Y \leq y_2\} -
P\{Y \leq y_1\} = \Phi\left(\frac{y_2-\mu}{\sigma}\right)
- \Phi\left(\frac{y_1-\mu}{\sigma}\right)$$
The table for $\Phi(x)$ does not list values for $x < 0$ because these
values can always be deduced via the relationship
$$\Phi(-x) = 1 - \Phi(x).$$
Thus, $\Phi(-1) = 1 - \Phi(1)$. So, for any normal random variable,
express the probability you want to find in terms of $\Phi(x)$, and then
look up values for $\Phi(x)$ in the table if $x \geq 0$, and
use $\Phi(x) = 1 - \Phi(|x|)$ if $x < 0$.
Finally, if all else fails, use a calculator such
as the one here
to check your answer.