We've got two numbers: 4231 and 620. Let's find their sum.

Step 1: We'll start by adding the digits 1 & 0 in column 1 and get 1.

Step 2: We'll start by adding the digits 3 & 2 in column 2 and get 5.

Step 3: We'll start by adding the digits 2 & 6 in column 3 and get 8.

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

So, 4231 + 620 = 4851.

