Okay, we are tasked with adding 505 and 561. Let's begin!

Step 1: We'll start by adding the digits 5 & 1 in column 1 and get 6.

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

Step 3: We'll start by adding the digits 5 & 5 in column 3 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

So, 505 + 561 = 1066.

