Not to worry, we've got 3421 and 436. Let's get to adding them!

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 & 3 in column 2 and get 5.

Step 3: We'll start by adding the digits 4 & 4 in column 3 and get 8.

Step 4: We'll start by adding the digits 3 & 0 in column 4 and get 3.

So, 3421 + 436 = 3857.

