Forecasts, tricasts, exactas
Put a price on each horse. A bookmaker forecast is not first × second. It is first, then second from whatever chance is left. Tote dividends are a different bet — a pool, not a starting price.
Name first and second in that order. One line. Bookmakers call the computer price a CSF.
Combinations1
Total stake£1.00
Estimated book price (this order)6.25 · 21/4
Return if that order hits£6.25
Profit£5.25
Each finishing order
A box pays the line that hits. You have already paid for the others.
- First → Second6.25 21/4
- Second → First5.25 17/4
Work it by hand
Take 5/2 to win and 6/4 to come second. Decimal is 3.50 and 2.50. Chance of the first is 1 ÷ 3.50. Chance of the second, once the winner is gone, is (1 ÷ 2.50) ÷ (1 − 1 ÷ 3.50). Multiply those two chances, then turn the answer upside down. That is (3.50 − 1) × 2.50 = 6.25. A £1 forecast returns £6.25. Profit £5.25. Same as 21/4.
A reverse forecast is that line and the other order, two stakes. Evens and evens in either order is two bets at even money: (2 − 1) × 2 = 2.00.
A tricast adds a third: after the first two are removed, divide the third horse’s chance by what is left. A box of four in a tricast is 4 × 3 × 2 = 24 lines. This desk uses that method. The unpublished computer-forecast table a shop prints can differ a little because of the overround. Tote is not this at all — it is a pool dividend to a £1 unit.