Sure thing! We've got 216 and 423 and we're gonna add them together.

Step 1: We'll start by adding the digits 6 & 3 in column 1 and get 9.

Step 2: We'll start by adding the digits 1 & 2 in column 2 and get 3.

Step 3: We'll start by adding the digits 2 & 4 in column 3 and get 6.

So, 216 + 423 = 639.

