We've got two numbers: 4105 and 8433. Let's find their sum.

Step 1: We'll start by adding the digits 5 & 3 in column 1 and get 8.

Step 2: We'll start by adding the digits 0 & 3 in column 2 and get 3.

Step 3: We'll start by adding the digits 1 & 4 in column 3 and get 5.

Step 4: We'll start by adding the digits 4 & 8 in column 4 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

So, 4105 + 8433 = 12538.

