Maths trick #2

Maths trick
>What is the square of (15)² ?
  Ans. 225
>What is the square of (65)² ?
  Ans. 4225
How is going on? 
Let's see!
Eg.       (15)²
        1×2|(5)²
            2|25  = 225

Eg.    (65)²
     6×7|(5)²
       42|25  =  4225
> see above table 
 Ten's place digit is multiply by its consecutive digit. 
& Square of Unit digit (unit digit 5 is compulsory), combining both you get Ans.

More Eg. 
          (85)²
      8×9|(5)²
        72| 25 = 7225
  
          (125)²
    12×13|(5)²
        156|25 = 15625

           (225)²
     22×23|(5)²
         506|25 = 50625

           (995)²
   99×100|(5)²
       9900|25 = 990025

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