(4 x 1000) + ( 8 + 100) + (1 + 10) + (0 x 1) + (8 x .1) + (2 x .01)

Let me google that for you

This is not an order of operations question, but rather it's about the powers of ten that are represented by the place of digits in a number. For example the number 567.3 = 5x100 + 6x10 +7x1 + 3x0.1.

To the OP: performing the operation is straight-forward - do you have a specific question? Buy the way, it appears you have a typo for the quantity in the tens place.