Now I'm going to show you how to subtract percents. If you're buying something at a store and you want to determine how much it's going to cost, after a ten percent discount.  Say the product costs one hundred and ten dollars, and you want to find out what that costs with a ten percent discount.  First, we find out what ten percent of the items value is. Which is the original value, multiplied by ten percent, or zero, point, one, zero.  This is the same as moving the decimal place one place over.  So from here, we go to there.  That equals eleven dollars.  So, the discount itself is eleven dollars.  So, to find out what you'll actually be paying, we borrow nine.  You'll be paying ninety-nine dollars.  So, ninety-nine dollars is the final price you pay, after a one hundred and ten dollar item has been marked down, ten per cent.  As another example, let's take an item that costs five hundred dollars, and we'll mark this down twenty per cent.  So, first let's find out what twenty per cent of five hundred is.  A quick and easy way to find out what twenty per cent of something is, is to find out what ten cent of it is, and multiply by two. Ten per cent would be fifty, times two, is one hundred dollars.  So, a twenty per cent discount on five hundred dollars is one hundred dollars.  So, your final price is the original price of the item, minus the discount. So, four hundred dollars is the final price after a five hundred dollar item had been marked down twenty percent.
