We are presented with 8224 and 644. Let's work out the sum.

Step 1: We'll start by adding the digits 4 & 4 in column 1 and get 8.

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

Step 3: We'll start by adding the digits 2 & 6 in column 3 and get 8.

Step 4: We'll start by adding the digits 8 & 0 in column 4 and get 8.

So, 8224 + 644 = 8868.

