Okay, we are given 5405 and 2574. Let's add them up step by step.

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 0 & 7 in column 2 and get 7.

Step 3: We'll start by adding the digits 4 & 5 in column 3 and get 9.

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

So, 5405 + 2574 = 7979.

