We are presented with 5123 and 8333. Let's work out the sum.

Step 1: We'll start by adding the digits 3 & 3 in column 1 and get 6.

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

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

Step 4: We'll start by adding the digits 5 & 8 in column 4 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

So, 5123 + 8333 = 13456.

