Extras
Additional runs can be gained by the batting team as extras (called "sundries" in Australia) due to errors made by the fielding side. This is achieved in four ways:
No ball: a penalty of one extra that is conceded by the bowler if he breaks the rules of bowling either by (a) using an inappropriate arm action; (b) overstepping the popping crease; (c) having a foot outside the return crease. In addition, the bowler has to re-bowl the ball. In limited overs matches, a no ball is called if the bowling team's field setting fails to comply with the restrictions. In shorter formats of the game (20–20, ODI) the free hit rule has been introduced. The ball following a front foot no-ball will be a free-hit for the batsman, whereby he is safe from losing his wicket except for being run-out.
Wide: a penalty of one extra that is conceded by the bowler if he bowls so that the ball is out of the batsman's reach; as with a no ball, a wide must be re-bowled. If a wide ball crosses the boundary, five runs are awarded to the batting side (one run for the wide, and four for the boundary).
Bye: extra(s) awarded if the batsman misses the ball and it goes past the wicketkeeper to give the batsmen time to run in the conventional way (note that one mark of a good wicketkeeper is one who restricts the tally of byes to a minimum).
Leg bye: extra(s) awarded if the ball hits the batsman's body, but not his bat, while attempting a legitimate shot, and it goes away from the fielders to give the batsmen time to run in the conventional way.
When the bowler has bowled a no ball or a wide, his team incurs an additional penalty because that ball (i.e., delivery) has to be bowled again and hence the batting side has the opportunity to score more runs from this extra ball. The batsmen have to run (i.e., unless the ball goes to the boundary for four) to claim byes and leg byes but these only count towards the team total, not to the striker's individual total for which runs must be scored off the bat.