We have numbers 1812 and 6166. Let's start adding them together.

Step 1: We'll start by adding the digits 2 & 6 in column 1 and get 8.

Step 2: We'll start by adding the digits 1 & 6 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 & 6 in column 4 and get 7.

So, 1812 + 6166 = 7978.

