The price: the decimals behind the shown odds
A price is a fraction before it is a number, and its decimals have to end somewhere. This page compares eight prices as they are displayed with the prices behind them, and measures the gap at a fixed stake.
- prices
- 8
- differ
- 4 of 8
- below
- 3
- above
- 1
A price shown to two decimal places is a rounded version of a fraction. On eight invented prices compared at a stake of 100.00, four paid a different amount from the one the display implied: three paid less and one paid more, and the gap ran from 0.28 to 0.50. The display and the price used are two different numbers.
Eight prices, two numbers each
Three of the eight fractions divide exactly into two decimals and five do not. Of those five, one rounds up on display and four round down, which is what produces the single case where the display promises more than the price pays.
| Fraction | Exact | Shown | Stored pays | Shown implies |
|---|---|---|---|---|
| 8/7 | 1.142857 | 1.14 | 114.28 | 114.00 |
| 4/3 | 1.333333 | 1.33 | 133.33 | 133.00 |
| 11/8 | 1.375 | 1.38 | 137.50 | 138.00 |
| 100/30 | 4.333333 | 4.33 | 433.33 | 433.00 |
| 9/4 | 3.25 | 3.25 | 325.00 | 325.00 |
| 6/5 | 1.20 | 1.20 | 120.00 | 120.00 |
| 5/2 | 2.50 | 2.50 | 250.00 | 250.00 |
| 1/2 | 1.50 | 1.50 | 150.00 | 150.00 |
| 8 prices | - | - | - | 4 differ |
Why a displayed price is a separate figure
A fractional price is rarely a clean two-decimal number, and an operator has to decide the precision it shows. Once that decision is made, the shown price and the used price are separate facts, and the difference is worth up to half a unit of the second decimal, multiplied by the stake. At 100.00 that is 0.50; at 1,000.00 it is 5.00. The reader's useful habit is not to distrust the price but to notice that the number on the button is a rounded rendering of a fraction, so the payout it implies and the payout it produces can differ by the rounding of the price itself - before any of the roundings on the stake, the return, the balance, the duty or the conversion have been applied.
- Where the operator shows a price as a fraction as well as a decimal, prefer the fraction: it is the price rather than a rendering of it.
- Do not read a two-decimal price as exact; where the fraction does not divide into two decimals it cannot be.
- Remember a displayed price can be above the used price as well as below it, as 11/8 was on sample R.
- Scale the gap by the stake: half a unit of the last shown decimal multiplied by the stake is the size of the question.
- Read how the operator rounds a return before assuming the displayed price is the one that settles it.