Mental Math

           

           There are so many things I have learned in school that I thought, “When am I ever going to use this information?”  The one lesson that I have never had second thoughts about was mental math.  I use mental math every day without fail.  Until I took these math courses, I never really knew just how often I use it.  It isn’t very often that I walk into a store that I don’t have to figure out a sale price or fill up with gas without first estimating how much it is going to cost me.  I just don’t understand why people rely on their phone calculator for so many things it would be easier to figure out themselves.

Thanks to my love of shopping, my percentage figuring skills are honed to near perfection.  I bet I could figure out a sale price faster than someone having to dig out their cell phone and type in the numbers.  When I see people in the store trying to figure out how much their shirt is going to cost with the 20% off sign looming over their head I just want to go over and explain just how easy it can be.  I always figure out what ten percent is and then adjust accordingly.  You have a $35.00 shirt for 20% off?  Ten percent of this would be $3.50 so 20% would be $7.00.  Your lovely new duds cost you a measly $28.00.  Voilà, it is just that easy.

Another place that I have been able to use this trick is when I am out to eat.  Who needs a tip calculator?  Once again, figure out ten percent and be a good patron and double it leaving my waiter a 20% tip for their hard work.  I have heard of another even faster trick that will allow you to leave a tip between 15-20% every time.  For bills under $100, take the first number of the total bill and double it.  For example, a $48.00 bill would have a tip of $8.00 which is roughly 16.5%.  Either way works just fine and is a faster way of supporting the wait staff.