A game label is not the full rule set
Roulette and blackjack each have variants. The table or game information should identify the rules that control the round, the accepted actions and the payout schedule. Do not assume that two games with the same name use the same settings. This article is a reading checklist rather than a strategy or recommendation.
For roulette, look for the wheel variant, available bets, how a bet is placed and the displayed payout schedule. For blackjack, check the dealer rules, available player actions, any side bets and how a winning hand is paid. The exact rule panel for the game is the authoritative description for that version.
Check stakes and age rules
All online gambling in Great Britain is for people aged 18 or over. UKGC rules set online-slot stake limits of £2 per game cycle for adults aged 18 to 24 and £5 for adults aged 25 and over. Those online-slot limits do not apply to roulette or blackjack. This does not mean there is no table limit; the specific game displays its own limits.
Do not treat a rule sheet as a way to guarantee an outcome. If you need to keep gambling spending within a boundary, use the payment controls guide or contact support. For probability terms, see RTP and volatility.