No problem, let's work through this together. We're starting with 4334 and 9912 and adding them all up.

Step 1: We'll start by adding the digits 4 & 2 in column 1 and get 6.

Step 2: We'll start by adding the digits 3 & 1 in column 2 and get 4.

Step 3: We'll start by adding the digits 3 & 9 in column 3 and get 12.
We'll write down the last digit 2 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, 4334 + 9912 = 14246.

