✔ 最佳答案
I'd prefer to answer the question by explaining it, rather than giving you the answer.
Anyway, a percentage basically means "a number out of a 100", so you can think of percentages as a fraction, but with the denominator being 100.
That being said, 20% really is 20/100 which is 1/5 in a simpified form, or 0.2 in decimals.
So to find 20% of 1489.59, you times 0.2(or 20/100 or 1/5 - they're all the same number) to 1489.59.
So on your page, it should look like 0.2 x $1489.59 = what ever your calculator spat out for you.