We are presented with 4226 and 3640. Let's work out the sum.

Step 1: We'll start by adding the digits 6 & 0 in column 1 and get 6.

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 4 & 3 in column 4 and get 7.

So, 4226 + 3640 = 7866.

