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Improving Your Mental Math Skills?

Posted by Cliff on from the outperforming-an-abacus dept.

Infrared-Archer asks: "I want to learn how to do most math calculations in my head. That way I won't have to reach for the calculator for problems I should be able to do mentally. Of course there are various websites (beat the calculator) that show many tricks, but I am looking for a comprehensive solution (books, websites) that shows how to solve of wide range of math problems mentally. Any suggestions?"

2 of 136 comments (clear)

  1. Best way by Arngautr · · Score: 5, Insightful

    The best way is to simply limit your calculator usage. I like to show off with the folks I tutor by doing their calculations in my head before they can type them into calculators. A strong basis in algebra can help you beak apart calculations into managable chunks, the trick is remembering how to put those chuncks back together. For instance (contrived example so not great but...): 95*23=100*25-100*2-5*23=2500-200-115=2185

    1. Re:Best way by jonjohnson · · Score: 5, Insightful

      And, my favorite trick is to multiply any number by 5, divide it by two, move the decimal place over (multiply by 10). It makes it much easer to grok that in my head, at least. So, 5*1024 is the same as 1024/2 * 10 = 512 * 10 = 5120.

      Work backwards for dividing by 5.