Okay, we are tasked with adding 1870 and 1105. Let's begin!

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

Step 2: We'll start by adding the digits 7 & 0 in column 2 and get 7.

Step 3: We'll start by adding the digits 8 & 1 in column 3 and get 9.

Step 4: We'll start by adding the digits 1 & 1 in column 4 and get 2.

So, 1870 + 1105 = 2975.

