first draft

@leapfrog-dipendra  @adhpawal  @bhuwang @anishmanandhar @Satish-Gupta @utsabneupane @Msanjib 
So, I guess you have already used StringBuilder previously. So, you could probably use something like , 

 `StringBuilder(initialNumber).reverse()`

i hven't checked i. But it is defintely there.

Soemtime it is better to explore all these functionality.