Telescope: discount: 30% sale price, $126

If your asking what 30% off of $126 item, its $88.20

First you change the percent to a decimal = 0.30
Then find what 30% of $126 is but multiplying 126 by 0.30 which equals 37.8. That is how much money is taken off. 
So now all you have to do is subtract 37.8 from 126 to get 88.2.