We have numbers 436 and 764. Let's start adding them together.

Step 1: We'll start by adding the digits 6 & 4 in column 1 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 3 & 6 in column 2 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 4 & 7 in column 3 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

So, 436 + 764 = 1200.

