(defun c:i2mm ();Convert Inches to MM
(setq i2m_a (getreal "\nEnter Inches: "))
(princ (strcat (rtos (* i2m_a 25.4) 2 3) " mm"))
(princ)
)

(defun c:mm2i ();Convert MM to Inches
(setq i2m_a (getreal "\nEnter Millimeters: "))
(princ (strcat (rtos (* i2m_a 0.0393700787) 2 3) " inches"))
(princ)
)