OK, let's do this. We've got 4442 and 8012 and we're adding them all together.

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

Step 2: We'll start by adding the digits 4 & 1 in column 2 and get 5.

Step 3: We'll start by adding the digits 4 & 0 in column 3 and get 4.

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, 4442 + 8012 = 12454.

