question: Mike needed a new pair of jeans.  When he got to the mall he saw that his favorite jeans were advertised 25% off.  The original price of the jeans was $40.  How much money will Mike have left over if he pays with a $50.00 bill?
answer: The jeans cost $40 and are sale for 25% off so 40 * .25 = $<<40*.25=10.00>>10.00 discount
  Take the original cost of the jeans and subtract the discount so 40-10 = $<<40-10=30.00>>30.00
  Mike pays with a $50 bill and the final cost of the jeans is $30 so 50-30 = $<<50-30=20.00>>20.00 left
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