A five-to-seven minute round on the one number an instalment offer never prints: what it costs a year. Each plan gives you the ticket price, the term, what you pay in the first instalment and in every one after it, and the shop's own wording for the fee — a rate per month, an annual fee rate, a one-off percentage, a flat sum, or no fee at all with a discount for paying in full. You estimate the annual cost as a nominal rate; within one percentage point of it, or six percent of it, whichever is wider, is a hit. Miss, and the plan opens payment by payment with the fee separated out of each one.
Nine plans in three stages of three. Stage one is the three rate-shaped fees over six to twelve instalments. Stage two adds the two that hide the number — a flat fee in money, and a plan with no fee where paying in full would have earned a discount — plus one three-way comparison. Stage three introduces no new way of writing a fee and halves the term, which is where the same fee turns into anything up to sixty percent a year. Forty seconds per plan, sixty for a comparison.
A keypad on the stage, so the system keyboard never covers the plan. Type an estimate in percent — the unit is a standing label beside the readout and is never yours to type — and press submit, or Enter. A physical keyboard works too: digits, the decimal point, Backspace and Enter. Text the game cannot read as a number leaves submit disabled, and that is not a wrong answer; only the clock running out scores a plan against you. A comparison is three cards you tap, or the 1, 2 and 3 keys. The rule of thumb stays on screen the whole round, with a button that opens what P and F are for each way of writing a fee.
Within one percentage point of the annual cost — or six percent of it, whichever is wider — is a hit: 100 points before multipliers. Within three points, or eighteen percent, scores half and keeps your streak. Anything further scores nothing and costs one of three lives. Stage two plans are worth 1.3 times as much and stage three 1.6. The multiplier rises half a step every three scoring answers, up to three times. There is no speed bonus: paying for speed would pay for guessing.
The round ends after the ninth plan, or when the third life goes — and the third miss still opens its payment table first, because that table is the point. The grade counts a hit as one and a near miss as half, weighted by stage, so a round of nine near misses is a C rather than a top grade. The result page lists all nine plans with your figure beside the nominal annual rate, the knowledge points from the ones you missed, and two standing cards: the simple-versus-compound conversion, and why a late fee is not in any of this.
Every round is dealt fresh from a seed. The share text carries one, and opening it deals the same nine plans with the same principals, terms and fees. "Play again" draws a new seed and drops the old one from the address bar, so a reload does not land back on the round you shared. Leaving mid-round keeps the plan you were on and the time that was left on it; the clock stops when the page is hidden and starts again when it is back.
Same arithmetic, same figures, both languages — the answer depends on a ratio, so one seed is one round either way, and only the currency symbol and the wording of the method differ. The five ways of writing a fee are the ways both markets write them: a handling fee charged monthly on the full price and an add-on annual rate are how mainland instalments are quoted, while a one-off fee and a pay-in-full discount are how instalment checkouts elsewhere are. The method word is on screen in both: 单利法 in Chinese, nominal in English. This site spells the English word instalment throughout; US sites spell the same thing installment, and nothing on either page changes with the spelling.
0.75% a month on a 12,000 purchase over twelve instalments is 90 a month in fees, which looks like 9% a year. It is 16.2%: the fee is charged on the full 12,000 every month while the principal you actually have falls to an average of 6,500. The monthly internal rate of return is 1.35137%, and 1.35137 × 12 is 16.22.
Source: Published commercial-bank instalment fee table, annualised fee rate (simple method)
The same 1.35137% a month is 16.2% a year by the simple method (× 12) and 17.5% compounded. Bank fee tables and US Regulation Z use the simple form; the People's Bank of China 2021 No. 3 annex uses the compound one. Neither is wrong — but a figure quoted without its method has two correct values, which is why every rate in this game carries the word for it.
Source: PBOC 2021 No. 3 annex; US Regulation Z, 12 CFR 1026
A one-off fee of 8.4% on a twelve-instalment plan is 16.3% a year taken with the first instalment, and less if it were taken with the last. That is why every plan card here states what you pay in the first instalment and in every one after it — the same total fee at a different moment is a different annual rate.
"No instalment fee, or pay in full and take 300 off" on a 6,000 purchase over twelve instalments is not free: you borrowed 5,700 and paid back 6,000, which is 9.6% a year. The two things the wording hides are that the fee is the forgone discount and that the loan is the price minus it.
US Regulation Z §1026.4(c)(2) excludes an actually incurred late charge from the finance charge, and the mainland disclosure rules require it stated separately from the cost of performing. So no plan in this game annualises one. It is a real cost — 4.1% of buy-now-pay-later orders in one US survey had been charged one, averaging $9.99 — but it belongs beside the rate, not inside it.
Source: US Regulation Z, 12 CFR 1026.4(c)(2)
Because of what the 0% is measured against. If paying in full would have earned you a discount, the discount you gave up is the cost of the instalments, and what you borrowed is the price minus it — not the price. On a 6,000 purchase with 300 off for paying in full, spread over twelve instalments, you borrowed 5,700 and repaid 6,000: about 9.6% a year.
The simple one: the monthly internal rate of return multiplied by twelve, labelled 单利法 in Chinese and nominal in English. That is the method published bank fee tables state and the method behind a US APR. Compounding the same monthly rate gives a higher figure — 16.2% becomes 17.5% — and the PBOC 2021 No. 3 annex uses that one. The result page shows the conversion.
24 × total fees ÷ (what you borrowed × (instalments + 1)). It is exact enough to land inside the hit band on every plan this game deals, which is why the game stops at twelve instalments: at eighteen and twenty-four the rule drifts 1.3 and 1.9 percentage points away from the nominal rate, outside its own band, and the game would be punishing the method it teaches.
Within one percentage point, or six percent of the answer, whichever is wider — so a 16% answer accepts 15 to 17, and a 40% answer accepts a wider window. Three points or eighteen percent scores half and keeps your streak. The bands are set so that the rule of thumb always lands inside the hit band and every common misreading always lands outside the near one: reading the headline figure can never score the same as working it out.
No, and deliberately. An incurred late charge is a contingent cost: US Regulation Z leaves it out of the finance charge and the mainland rules require it stated apart from the cost of performing. Folding it into an annual rate would teach a worst case as if it were a disclosure. It is in a knowledge card on the result page instead.
Yes, within the same parameter table. The link carries the seed, and the seed fixes the purposes, the principals, the terms, the fees and the order. The same seed is also the same round in both languages, down to the figures — the answer depends on a ratio, so only the currency symbol and the wording of the method change.
Rates and repayment figures are worked examples. No loan, card or insurance product is recommended, arranged or referred.
