We are presented with 810 and 153. Let's work out the sum.

Step 1: We'll start by adding the digits 0 & 3 in column 1 and get 3.

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.

So, 810 + 153 = 963.

