Varible Need Help VERY FAST

hi,
i if this topic is already there sry but here is my problem:
my math teacher told me to make a programm where i can put i a number for example 20 and it should be the Root come out i dont know if this is right word (in German Wurzel)
Like this you put in: 16 and it come out 4
Thanks for help
Johannes

num=INPUT("ENTER A NUMBER:")
num=num^.5
PRINT "THE SQUARE ROOT OF THAT NUMBER IS: "+num

The square root is equal to the number raised to the .5 power.

http://www.blitzbasic.com/bpdocs/command.php?name=Sqr&ref=2d_cat

THANKS !!!!