The first thing we have to do is find 20% of 20. To do this we cross multiply :
(20 / 100 ) * (20 / 1)
Then we simplify
(20 / 5) * (1 / 1)
( 4 ) * ( 1 ) =
4
So we get four. Now remember this is not our final answer. We have to subtract it from the total which is 20. We subtract it because since the price is discounted, it will go down. Also because we just found 20% OF 20 , not 20 minus 20% of twenty.
