You are required to report your winnings\n\n For example, if you winR$620 from a horse race but it cost youR$20 to bet, your taxable winnings areR$620, notR$600 after subtracting yourR$20 wager. You are not permitted to "net" your winnings and losses. Cash is not the only kind of winnings you need to report.

an agreement to risk money on the unknown result of an event in the hope of winning more money than you have risked, or the amount of money risked; a bet.