Solution

 PROGRAM test
  IMPLICIT NONE
  INTEGER throw_dice,th
   DO I = 1,100
    th = throw_dice()
    PRINT*, 'total throw= ', th
   END DO
 END PROGRAM
 FUNCTION throw_dice()
  IMPLICIT NONE
  INTEGER :: throw_dice
  INTEGER :: throw1,throw2
   CALL RANDOM_NUMBER(r)
      ! r is returned 0 <= r <= 1
      ! NINT(r*5) gives an integer between 0 and 5
   throw1 = 1 + NINT(r*5)
   PRINT*, 'throw1= ', throw1
   CALL RANDOM_NUMBER(r)
   throw2 = 1 + NINT(r*5)
   PRINT*, 'throw2= ', throw2
   throw_dice = throw1 + throw2
 END FUNCTION