We have numbers 156 and 3412. Let's start adding them together.

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

Step 2: We'll start by adding the digits 5 & 1 in column 2 and get 6.

Step 3: We'll start by adding the digits 1 & 4 in column 3 and get 5.

Step 4: We'll start by adding the digits 0 & 3 in column 4 and get 3.

So, 156 + 3412 = 3568.

