1. The problem is to add two 3-digit numbers vertically. 2. The formula for addition is: $$\text{Sum} = \text{Number}_1 + \text{Number}_2$$ 3. Important rules: - Add digits starting from the rightmost column (units). - Carry over if the sum of digits exceeds 9. 4. Example: Add 216 + 84 Step 1: Add units: $6 + 4 = 10$ (write 0, carry 1) Step 2: Add tens: $1 + 1 + 8 = 10$ (write 0, carry 1) Step 3: Add hundreds: $2 + 1 = 3$ So, $$216 + 84 = 300$$ 5. Another example: Add 229 + 56 Step 1: Units: $9 + 6 = 15$ (write 5, carry 1) Step 2: Tens: $2 + 5 + 1 = 8$ Step 3: Hundreds: $2$ So, $$229 + 56 = 285$$ 6. This method applies to all problems listed. Final answer for the first problem: $$216 + 84 = 300$$