No problem, let's work through this together. We're starting with 7013 and 840 and adding them all up.

Step 1: We'll start by adding the digits 3 & 0 in column 1 and get 3.

Step 2: We'll start by adding the digits 1 & 4 in column 2 and get 5.

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

Step 4: We'll start by adding the digits 7 & 0 in column 4 and get 7.

So, 7013 + 840 = 7853.

