Let's solve this addition problem. We have 850 and 2108, and we need to add them together.

Step 1: We'll start by adding the digits 0 & 8 in column 1 and get 8.

Step 2: We'll start by adding the digits 5 & 0 in column 2 and get 5.

Step 3: We'll start by adding the digits 8 & 1 in column 3 and get 9.

Step 4: We'll start by adding the digits 0 & 2 in column 4 and get 2.

So, 850 + 2108 = 2958.

