20% off $200 = $160. You save $40.
Equation: $200 − (20% × $200) = $200 − $40 = $160.
Another way to read it: you pay 80% of the original price — that's $160.
$160. The discount is $40 and the final price you pay is $160.
You pay $160 (before tax). That's $200 minus a $40 discount.