We are presented with 3084 and 8211. Let's work out the sum.

Step 1: We'll start by adding the digits 4 & 1 in column 1 and get 5.

Step 2: We'll start by adding the digits 8 & 1 in column 2 and get 9.

Step 3: We'll start by adding the digits 0 & 2 in column 3 and get 2.

Step 4: We'll start by adding the digits 3 & 8 in column 4 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

So, 3084 + 8211 = 11295.

