Each control is worth a certain number of points, determined by the first digit (25 and 27 both score 20 points; 45 and 49 both score 40 points; etc.) You can visit them in any order between the start and the finish and do not have to get them all. Make sure you finish in time - 30 points are deducted for every minute you take over the time limit (1 second over loses 30 points; 2m50 over loses 90 points; etc.)