Let's get this math done. We have 81 and 4 and we're going to add them all together.

Step 1: We'll start by adding the digits 1 & 4 in column 1 and get 5.

Step 2: We'll start by adding the digits 8 & 0 in column 2 and get 8.

So, 81 + 4 = 85.

