We have numbers 6363 and 406. Let's start adding them together.

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 6 & 0 in column 2 and get 6.

Step 3: We'll start by adding the digits 3 & 4 in column 3 and get 7.

Step 4: We'll start by adding the digits 6 & 0 in column 4 and get 6.

So, 6363 + 406 = 6769.

