Let's solve this addition problem. We have 2638 and 2040, and we need to add them together.

Step 1: We'll start by adding the digits 8 & 0 in column 1 and get 8.

Step 2: We'll start by adding the digits 3 & 4 in column 2 and get 7.

Step 3: We'll start by adding the digits 6 & 0 in column 3 and get 6.

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

So, 2638 + 2040 = 4678.

