#### Answer

$-5$

#### Work Step by Step

We start with the given expression: $3-8$
First, we will convert this to an addition problem, using the definition of subtraction: $3+(-8)$
We can find the sum of a positive and a negative integer by subtracting the smaller absolute value from the larger absolute value and giving the result the sign of the original number that has the larger absolute value.
Since $|-8|>|3|$, we can subtract $3$ from $8$, giving us $5$. Since the large number was originally negative, we give our result the negative sign: $-5$