The Rule, Before Anything Else
Every price in American odds is either a minus number or a plus number, and the sign is doing a job most people never have explained to them.
A minus price tells you what you have to put up to win 100. At -150 you risk 150 to win 100. At -110 you risk 110 to win 100.
A plus price tells you what you win if you put up 100. At +100 you risk 100 to win 100. At +130 you risk 100 to win 130.
So when a card says "2 units" next to a minus price, that is two units being won. When it says "1 unit" next to a plus price, that is one unit being risked. Same words, opposite meaning, and the only thing that flips it is the sign.
What That Does To Tonight's Card
Run the four plays through the rule and the true shape of the day appears.
| Play | Price | Units as written | Actually risking | Actually winning |
|---|---|---|---|---|
| Reds team total under 3.5 | -150 | 2 | 3.000 | 2.000 |
| Braves team total under 4.5 | -145 | 1.5 | 2.175 | 1.500 |
| Phillies and Astros under 8 | -110 | 1 | 1.100 | 1.000 |
| Blue Jays and Athletics over 9.5 | +100 | 1 | 1.000 | 1.000 |
| Card | 5.5 | 7.275 | 5.500 |
Notice the Athletics row. It is the only line where the risk column and the win column are the same number, and that is not a coincidence. +100 is the exact point where the two meanings meet. Every price below it on the minus side risks more than it wins. Every price above it on the plus side wins more than it risks.
That makes +100 a useful thing to keep in your head as a marker. If you can find your opinion at plus money, you are being paid more than even money for it. If you are at a minus price, you are paying for the privilege of being on that side.
Working Out The Break Even
Every price implies a win rate. Here is the arithmetic, and it is genuinely one line.
For a minus price, take the number without its sign, and divide it by that number plus 100. So -150 becomes 150 divided by 250, which is 60.00 percent. And -110 becomes 110 divided by 210, which is 52.38 percent.
For a plus price, divide 100 by the number plus 100. So +100 becomes 100 divided by 200, which is 50.00 percent.
Do that for all four and you get 60.00, 59.18, 52.38 and 50.00. Those are the four bars each individual ticket has to clear just to stay level.
The Break Even For The Whole Card
A card has its own number and it is not the average of the four. It is total risk divided by total risk plus total win.
7.275 divided by 12.775 is 56.95 percent. That is what this whole day needs, across all four bets, to come out at zero.
Here is the part worth sitting with. The steepest single leg on this card needs 60 percent. The card needs 56.95. Adding the cheaper bets pulled the day's bar down, not up. That is the opposite of what most people assume happens when they add legs, and the reason it works is that these are four separate tickets and not a parlay. A parlay multiplies the requirement. Four singles average it.
The Mistake This Is All Guarding Against
Say you read this card quickly and counted 5.5 units of exposure, because that is the number the unit column adds up to.
You would be short by 1.775 units, which is about 32 percent of what you thought you had at stake. If your unit is 50 dollars, you thought you had 275 in play and you actually have 363.75.
That gap comes entirely from the three minus prices. The plus price is the only one where the two numbers agree, and it is the smallest bet on the card.
| If tonight goes | Result |
|---|---|
| All four win | +5.500 units |
| Reds under loses, other three win | +0.500 units |
| Reds and Braves lose, other two win | -3.175 units |
| Only the Athletics over wins | -5.275 units |
| All four lose | -7.275 units |
Look at the second row. Three of four bets can win and the day is barely above water, because the one that lost was the one carrying 41 percent of the money. That is worth knowing before first pitch rather than after the last one.
The Habit To Build
Three things, and they take under a minute together.
One. Read the sign before you read the number. Minus means the unit figure is what you win. Plus means it is what you risk. That single check fixes almost every miscounted card.
Two. Convert each price to its break even before you take it. If the number is 60.00 percent and you cannot honestly say you think this wins three times in five, look for the same opinion at a shorter price or leave it.
Three. Add the risk column, not the unit column. The risk column is the amount of money that is actually on the table tonight, and it is the only one your bankroll notices.