We are presented with 356 and 6205. Let's work out the sum.

Step 1: We'll start by adding the digits 6 & 5 in column 1 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 5 & 0 in column 2 and get 6.

Step 3: We'll start by adding the digits 3 & 2 in column 3 and get 5.

Step 4: We'll start by adding the digits 0 & 6 in column 4 and get 6.

So, 356 + 6205 = 6561.

