In the rule Form Sheet, change “optionally, its Odds” to “its Odds”.

In the same rule, change “and the required number of Participants for that Sport; it can also have an Odds, and should (if it occurred in the past)” to “an Odds, and the required number of Participants for that Sport; it should also (if it occurred in the past)”.

Add a new subrule to the rule Form Sheet, called Odds, with the following text:

All Potential Outcomes on each Sporting Event have Odds, which are the Odds on that outcome being offered by the Bookie. Odds are expressed in the form “X-to-Y” or “X:Y”, where X and Y are integers greater than 0, and are listed next to each Potential Outcome. When a Sporting Event is created, the values of X and Y for each Odds must be determined using the rules for the Sport identified in the Sporting Event. If no such rules for determining Odds exist for a Sport, then Odds for all outcomes are the default value, which is 11:10.

Whenever a Punter places a Bet, they must, for each Outcome of the Sporting Event for that Bet, increase the X in the Odds for that outcome by the 1; then they increase the Y of the Odds of the selected Outcome for the selected Sporting Event by the Stake of their Bet, divided by 10, and then rounded down to the nearest integer (to a minimum of 1).

Change the rule Betting to read as follows:

At any time, a Punter may place a Bet on any Sporting Event that they have not previously placed a Bet on. Bets placed are publicly tracked and must have the following elements:
* The name of the Punter placing the Bet
* A single, specific Sporting Event (identified by the Sport and the date on which it will occur) that has not yet occurred
* An outcome (defined in the rule for the Sport of that Sporting Event)
* A Stake (which must be a positive quantity of Readies that is not greater than the amount of Readies that Punter has, minus the Stakes of any other open Bets that Punter has)
* A Purchase Odds (which is the Odds on the selected Outcome at the time at which the Bet is placed, before Odds are updated on the basis of their own Bet)

Whenever a Punter places a Bet they must update Odds as described in the rule Odds.

After a Sporting Event has occurred, the Bookie should Cash all Bets for that Sporting Event, as an atomic action with the following steps:
* Remove all such Bets from public tracking
* For each Bet’s whose Outcome occured, increase the Readies of the betting Punter by the amount of the Stake multiplied by X and divided by Y, where X and Y are the values from the Purchase Odds of that Bet.
* For each Bet whose Outcome did not occur, decrease the Readies of the betting Punter by the amount of the Stake.