We've got two numbers: 8603 and 6280. Let's find their sum.

Step 1: We'll start by adding the digits 3 & 0 in column 1 and get 3.

Step 2: We'll start by adding the digits 0 & 8 in column 2 and get 8.

Step 3: We'll start by adding the digits 6 & 2 in column 3 and get 8.

Step 4: We'll start by adding the digits 8 & 6 in column 4 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

So, 8603 + 6280 = 14883.

