OK, let's do this. We've got 2134 and 3403 and we're adding them all together.

Step 1: We'll start by adding the digits 4 & 3 in column 1 and get 7.

Step 2: We'll start by adding the digits 3 & 0 in column 2 and get 3.

Step 3: We'll start by adding the digits 1 & 4 in column 3 and get 5.

Step 4: We'll start by adding the digits 2 & 3 in column 4 and get 5.

So, 2134 + 3403 = 5537.

