Alright, let's solve this problem step by step. We have 1395 and 5064 and we're adding them together.

Step 1: We'll start by adding the digits 5 & 4 in column 1 and get 9.

Step 2: We'll start by adding the digits 9 & 6 in column 2 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 3 & 0 in column 3 and get 4.

Step 4: We'll start by adding the digits 1 & 5 in column 4 and get 6.

So, 1395 + 5064 = 6459.

