Okay, we are given 5040 and 2900. Let's add them up step by step.

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

Step 2: We'll start by adding the digits 4 & 0 in column 2 and get 4.

Step 3: We'll start by adding the digits 0 & 9 in column 3 and get 9.

Step 4: We'll start by adding the digits 5 & 2 in column 4 and get 7.

So, 5040 + 2900 = 7940.

