1. **State the problem:** We are given that the sum is 4 and we need to find the value of $q$. 2. **Interpretation:** The problem is incomplete as stated, but typically "the sum is 4 and q" suggests an equation involving $q$ where the sum equals 4. 3. **Assuming the sum refers to $q + x = 4$ for some $x$:** 4. **Formula:** To find $q$, rearrange the equation: $$q = 4 - x$$ 5. **Explanation:** Without additional information about $x$, $q$ depends on $x$. If $x$ is known, substitute it to find $q$. 6. **Conclusion:** More information is needed to find a unique value for $q$. If the problem means $q$ itself is the sum equal to 4, then $q = 4$.