Let's get this math done. We have 1255 and 2644 and we're going to add them all together.

Step 1: We'll start by adding the digits 5 & 4 in column 1 and get 9.

Step 2: We'll start by adding the digits 5 & 4 in column 2 and get 9.

Step 3: We'll start by adding the digits 2 & 6 in column 3 and get 8.

Step 4: We'll start by adding the digits 1 & 2 in column 4 and get 3.

So, 1255 + 2644 = 3899.

