1. Let's solve a simple addition problem suitable for grade 3: What is 7 + 5? 2. The formula for addition is: $$a + b = c$$ where $a$ and $b$ are numbers you add, and $c$ is the result. 3. Here, $a = 7$ and $b = 5$. So, we calculate: $$7 + 5 = 12$$ 4. This means when you add 7 and 5 together, you get 12. 5. Addition is combining two groups of objects to find out how many there are in total. Final answer: 12