OK, let's do this. We've got 5454 and 540 and we're adding them all together.

Step 1: We'll start by adding the digits 4 & 0 in column 1 and get 4.

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 4 & 5 in column 3 and get 9.

Step 4: We'll start by adding the digits 5 & 0 in column 4 and get 5.

So, 5454 + 540 = 5994.

