We've got two numbers: 816 and 8153. Let's find their sum.

Step 1: We'll start by adding the digits 6 & 3 in column 1 and get 9.

Step 2: We'll start by adding the digits 1 & 5 in column 2 and get 6.

Step 3: We'll start by adding the digits 8 & 1 in column 3 and get 9.

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

So, 816 + 8153 = 8969.

