Here we go! We're going to add 8363 and 121 together.

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

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

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

Step 4: We'll start by adding the digits 8 & 0 in column 4 and get 8.

So, 8363 + 121 = 8484.

