We have numbers 402 and 497. Let's start adding them together.

Step 1: We'll start by adding the digits 2 & 7 in column 1 and get 9.

Step 2: We'll start by adding the digits 0 & 9 in column 2 and get 9.

Step 3: We'll start by adding the digits 4 & 4 in column 3 and get 8.

So, 402 + 497 = 899.

