We've got two numbers: 156 and 3711. Let's find their sum.

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

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 & 7 in column 3 and get 8.

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

So, 156 + 3711 = 3867.

