Code:
ON *:TEXT:*!calc*:#:{ 
  set %nulle $2 * 0.000025
  msg # Total: %nulle BTC!
}


That is what I have....

my question is how to set so that it see's $2 as a number, and if anything else, it just messages "use a number"

like:

!calc 1000
returns: Total: 0.025btc

and
!calc taco
returns: Please Use a Number