We've got two numbers: 1230 and 4023. Let's find their sum.

Step 1: We'll start by adding the digits 0 & 3 in column 1 and get 3.

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 & 0 in column 3 and get 2.

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

So, 1230 + 4023 = 5253.

