Independent guide
This independent RK 89 guide supplies its own free Common Factor Roulette demo. Operator identity, domains, licence, apps, payments, support and commercial game equivalence have not been independently verified. No operator account or commercial link is supplied here.
Two draws and their greatest common divisor
One paid round draws two independent uniform pockets numbered 0–12. Score is their greatest common divisor, with gcd(0,0)=0. Choose score band 0–4, 5–8 or 9–12 before spinning. All 169 ordered pairs are equally likely.
Exact169-pair enumeration
There are 141 winning ordered pairs for scores 0–4, 16 for 5–8 and 12 for 9–12. For example, draws 6 and 9 have gcd 3, draws 0 and 8 score 8, and draws 0 and 0 score 0. Multipliers use these exact counts, not the number of score labels.
Displayed hit probability and total return
The hit probabilities are 141/169,16/169 and 12/169. Total-return multipliers are 1.150638298,10.14 and 13.52 respectively. A hit returns stake×0.96×169 divided by the selected winning-pair count, including stake; a miss returns zero.
One stake and one settlement
Select a band and virtual stake before starting. One stake is deducted, and both independent draws settle together. Settings, start and refill are locked during the round. A matching GCD score pays the displayed total return; any other score returns zero. There is no mid-round cash-out or additional stake for the second draw.
Frequently asked questions
Is this an operator site?
This independent RK 89 guide supplies its own free Common Factor Roulette demo. Operator identity, domains, licence, apps, payments, support and commercial game equivalence have not been independently verified. No operator account or commercial link is supplied here.
How is the score calculated?
One paid round draws two independent uniform pockets numbered 0–12. Score is their greatest common divisor, with gcd(0,0)=0. Choose score band 0–4, 5–8 or 9–12 before spinning. All 169 ordered pairs are equally likely.
How are bands priced?
There are 141 winning ordered pairs for scores 0–4, 16 for 5–8 and 12 for 9–12. For example, draws 6 and 9 have gcd 3, draws 0 and 8 score 8, and draws 0 and 0 score 0. Multipliers use these exact counts, not the number of score labels.
What return is displayed?
The hit probabilities are 141/169,16/169 and 12/169. Total-return multipliers are 1.150638298,10.14 and 13.52 respectively. A hit returns stake×0.96×169 divided by the selected winning-pair count, including stake; a miss returns zero.
How many stakes does a round cost?
Select a band and virtual stake before starting. One stake is deducted, and both independent draws settle together. Settings, start and refill are locked during the round. A matching GCD score pays the displayed total return; any other score returns zero. There is no mid-round cash-out or additional stake for the second draw.
What does96% expected return mean?
Exact expected return is 96% in every band: hit probability multiplied by the total-return multiplier is 0.96. Bands change hit frequency and variance, not expectation. A 96% expectation is not a promise of a single spin or a short session. This demo does not certify an external operator or reproduce its games.
What survives reload?
Settled balance and fractional payout carry persist in localStorage. Reloading during a round ends it without refunding its deducted stake. Outside a round, refill sets 1000 coins when balance is below the smallest stake; it does not add 1000 or erase fractional carry. Band and stake return to defaults on reload.
What data can be exposed?
There are no account, payment or identity-document forms here. Fonts, the visit counter, server and CDN requests can expose technical data including IP and browser details. Complete anonymity, third-party data use and cookie lifetimes are not established. Clearing cache alone may leave localStorage intact.
Are external claims verified?
A matching brand, professional design, search result or HTTPS connection does not verify ownership, authorisation or safety. Match any claim against an independent regulator register, including entity, current status, scope and listed domains. No operator licence or service is endorsed here.
How can I limit a session?
This demo is restricted to adults 18+ and uses coins without cash value or prizes. Set session time and virtual-coin limits before playing, then stop at those limits. Raising a stake to recover losses does not improve expectation. If playing affects responsibilities or becomes hard to control, stop and seek suitable independently verified local support.
Explore the original free Common Factor game and its score bands.
