We have numbers 8124 and 261. Let's start adding them together.

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

Step 2: We'll start by adding the digits 2 & 6 in column 2 and get 8.

Step 3: We'll start by adding the digits 1 & 2 in column 3 and get 3.

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

So, 8124 + 261 = 8385.

