Here we go! We're going to add 3117 and 3121 together.

Step 1: We'll start by adding the digits 7 & 1 in column 1 and get 8.

Step 2: We'll start by adding the digits 1 & 2 in column 2 and get 3.

Step 3: We'll start by adding the digits 1 & 1 in column 3 and get 2.

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

So, 3117 + 3121 = 6238.

