two tricks of math

Always remember these two tricks of math

1.   multiply with 9,99,999,9999 and ........

       Simply 8473859*99=8473859*(100-1)   like this for 9,999,9999, and etc

       2.     Multiply by 5 15 25 35 45   etc

   

        Simply   79459485*25=79459485*(100/4)

        Simply   79459485*15=79459485*(30/2)

        Simply   79459485*5=79459485*(10/2)

              and so on ................

Any problem post comment here  .........