We are presented with 4008 and 9854. Let's work out the sum.

Step 1: We'll start by adding the digits 8 & 4 in column 1 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 0 & 5 in column 2 and get 6.

Step 3: We'll start by adding the digits 0 & 8 in column 3 and get 8.

Step 4: We'll start by adding the digits 4 & 9 in column 4 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

So, 4008 + 9854 = 13862.

