Not to worry, we've got 8351 and 1340. Let's get to adding them!

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

Step 2: We'll start by adding the digits 5 & 4 in column 2 and get 9.

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

Step 4: We'll start by adding the digits 8 & 1 in column 4 and get 9.

So, 8351 + 1340 = 9691.

