Okay, we are given 1354 and 4125. Let's add them up step by step.

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

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

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

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

So, 1354 + 4125 = 5479.

