1. The problem is to calculate $1 - 1$. 2. The subtraction operation is defined as taking away the second number from the first. 3. Using the formula for subtraction: $$a - b = c$$ where $a=1$ and $b=1$. 4. Substitute the values: $$1 - 1 = 0$$. 5. Therefore, the result of $1 - 1$ is $0$.