Using AND or OR
You can use AND or OR functions in a formula to make it even more powerful. Let's take the above example but add an extra finish to QA (platinum). The discount we want to take of (when you buy more then 5 products) is not valuable on platinum. We need to use both AND and OR to accomplish this:
IF(AND(QB > 5, OR(QA = 100, QA = 200)), QA * QB * 0.8, QA * QB)
The above formula does this: If Product Amount is greater then 5 and product finish is either silver or gold, apply the discount, else don't apply the discount.