1. The problem is to understand what it means when the denominator of a fraction is 1. 2. A fraction is written as $\frac{a}{b}$ where $a$ is the numerator and $b$ is the denominator. 3. If the denominator $b=1$, then the fraction simplifies to just the numerator $a$ because dividing by 1 does not change the value. 4. For example, $\frac{5}{1} = 5$ and $\frac{-3}{1} = -3$. 5. So, if your answer has a denominator of 1, you can simply write the answer as the numerator alone. 6. This means your answer is an integer or whole number without any fractional part. Final answer: When the denominator is 1, the fraction equals the numerator itself.