The following procedures provide command interfaces to the
       expr math functions. They take the same arguments  as  the
       expr functions and may take expressions as arguments.

              abs         acos        asin       atan2
              atan        ceil        cos        cosh
              double      exp         floor      fmod
              hypot       int         log10      log
              pow         round       sin        sinh
              sqrt        tan         tanh

       These procedures are provided by Extended Tcl.