1. The user requests 100 questions involving addition, multiplication, and Bayes' theorem. 2. According to the guest rule, we will solve only the first problem completely, which is addition. 3. Let's state a simple addition problem: Calculate $7 + 5$. 4. The formula for addition is $a + b = c$, where $a$ and $b$ are numbers and $c$ is their sum. 5. Applying the formula: $7 + 5 = 12$. 6. Therefore, the answer is $12$.