How To Create an IFS Formula based on X?

Hello, does anybody know how to create an IF based formula.

The structure:

  • Product Type (Dropdown Field)
  • Amount (Currency Field)
  • Value A (Currency Field)
  • Value B (Currency Field)
  • Value C (Currency Field)
  • Value D (Currency Field)

IF Product Type = Product A

THEN Amount = Value A * Value B

IF Product Type = Product B

THEN Amount = Value C * Value D

Kindly advise, thank you.