We've got two numbers: 2039 and 6456. Let's find their sum.

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

Step 2: We'll start by adding the digits 3 & 5 in column 2 and get 9.

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

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

So, 2039 + 6456 = 8495.

