We are presented with 9900 and 4943. Let's work out the 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 0 & 4 in column 2 and get 4.

Step 3: We'll start by adding the digits 9 & 9 in column 3 and get 18.
We'll write down the last digit 8 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 9 & 4 in column 4 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

So, 9900 + 4943 = 14843.

