We are presented with 5107 and 3644. Let's work out the sum.

Step 1: We'll start by adding the digits 7 & 4 in column 1 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 0 & 4 in column 2 and get 5.

Step 3: We'll start by adding the digits 1 & 6 in column 3 and get 7.

Step 4: We'll start by adding the digits 5 & 3 in column 4 and get 8.

So, 5107 + 3644 = 8751.

