Okay, we are given 2313 and 6646. Let's add them up step by step.

Step 1: We'll start by adding the digits 3 & 6 in column 1 and get 9.

Step 2: We'll start by adding the digits 1 & 4 in column 2 and get 5.

Step 3: We'll start by adding the digits 3 & 6 in column 3 and get 9.

Step 4: We'll start by adding the digits 2 & 6 in column 4 and get 8.

So, 2313 + 6646 = 8959.

