Okay, we are given 115 and 1503. Let's add them up step by step.

Step 1: We'll start by adding the digits 5 & 3 in column 1 and get 8.

Step 2: We'll start by adding the digits 1 & 0 in column 2 and get 1.

Step 3: We'll start by adding the digits 1 & 5 in column 3 and get 6.

Step 4: We'll start by adding the digits 0 & 1 in column 4 and get 1.

So, 115 + 1503 = 1618.

