1. The problem is to understand when to use subtraction or addition in math operations. 2. Addition is used to combine quantities, while subtraction is used to find the difference between quantities. 3. The formula for addition is $a + b$, which means combining $a$ and $b$. 4. The formula for subtraction is $a - b$, which means taking $b$ away from $a$. 5. Important rule: Addition increases the value, subtraction decreases the value. 6. Example: If you have 5 apples and get 3 more, you add: $5 + 3 = 8$ apples. 7. Example: If you have 8 apples and give away 3, you subtract: $8 - 3 = 5$ apples. 8. Always decide based on whether you are combining quantities (add) or finding how much is left/difference (subtract).