Okay, we are tasked with adding 3515 and 6100. Let's begin!

Step 1: We'll start by adding the digits 5 & 0 in column 1 and get 5.

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 5 & 1 in column 3 and get 6.

Step 4: We'll start by adding the digits 3 & 6 in column 4 and get 9.

So, 3515 + 6100 = 9615.

