We are presented with 4981 and 6906. Let's work out the sum.

Step 1: We'll start by adding the digits 1 & 6 in column 1 and get 7.

Step 2: We'll start by adding the digits 8 & 0 in column 2 and get 8.

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 4 & 6 in column 4 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

So, 4981 + 6906 = 11887.

