We have numbers 821 and 1016. Let's start adding them together.

Step 1: We'll start by adding the digits 1 & 6 in column 1 and get 7.

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

Step 3: We'll start by adding the digits 8 & 0 in column 3 and get 8.

Step 4: We'll start by adding the digits 0 & 1 in column 4 and get 1.

So, 821 + 1016 = 1837.

