Okay, we are tasked with adding 4531 and 9951. Let's begin!

Step 1: We'll start by adding the digits 1 & 1 in column 1 and get 2.

Step 2: We'll start by adding the digits 3 & 5 in column 2 and get 8.

Step 3: We'll start by adding the digits 5 & 9 in column 3 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

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

So, 4531 + 9951 = 14482.

