Three more than a number is $-5$. How do you find the number?

Hint: We first try to make the given written statement in its mathematical form. We assume the variable $x$ to as the required number. Then we form a relationship. We then solve the given linear equation by simplifying the equation with the help of the binary operation. We get the value of the variable as the solution.

Complete answer:
The given statement about the required number is that three more than the number is $-5$.
Let us start by assuming that the required number is $x$. Then we have been given that three more than the number $x$ is $-5$. This means that if we add 3 to the number $x$ , then we will get $-5$.
So, now we can form the mathematical statement as $x+3=-5$.
Now we will apply the binary operation of subtraction to simplify the equation to get the value of $x$. We will take the variables and the constants separately on the opposite sides of the equality. Then we will get
$\begin{align}
  & x+3=-5 \\
 & \Rightarrow x=-5-3=-8 \\
\end{align}$
Therefore, we will get the required number as $x=-8$.

Note: We can also solve the system according to the value of $-5$. As the required number is three more than the number $-5$, we can say that the required number is three less than the number $-5$. Now we subtract 3 from $-5$ which in mathematical form gives us $-5-3=-8$. The final answer still remains $-8$ for the required number.