We've got two numbers: 8071 and 455. Let's find their sum.

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

Step 2: We'll start by adding the digits 7 & 5 in column 2 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 0 & 4 in column 3 and get 5.

Step 4: We'll start by adding the digits 8 & 0 in column 4 and get 8.

So, 8071 + 455 = 8526.

