Fast Track Multiplication Techniques or Tricks

Tricks 4

Finding the square of a number ending with 5.

In such cases, number coming before 5, say n, is multiplied with n+1 and 25 is put at the right end of the result obtained n(n+1).

Example - Find the square of 35.
Solution.   Here, n=3
According to the rule, n(n+1)=3(3+1)=3*4=12
Therefore- Required square = 1225
                                     n(n+1)   25 is put at the right end of n(n+1)
                                                  or 12 to get the required square of 35.

Example - Finding the square of 145.
Solution - Here, n=14
According to the rule, n(n+1)=14(14+1)=14*15=210
Therefore- Required square =21025
                                     n(n+1)   25 is put at the right end of n(n+1)
                                                  or 210 to get the required square of 145.