How to Play Odds and Evens

Odds and Evens, also known as Morra, is a simple 2-player game that dates back to the Roman Empire.^[1] It’s a great activity to pass the time on a long car ride or rainy day. Since Odds and Even is based entirely on luck, anyone with basic math skills can join in on the fun. Invite a friend or family member and see if the “odds” are in your favor!

[Edit]Steps

[Edit]Reviewing the Rules

1. Announce to your opponent that you want to represent “odds” or “evens.” Talk with the other player and pick a “side” to represent. This process is very similar to “heads” or “tails.” There is no advantage to either of them, so you can just pick what you want.^[2]
   
   • There isn’t a “youngest picks first” rule to this game. Just try to agree on who will represent each side!
   • For example, if you decide you are "evens," your opponent has to be "odds."
2. Choose a number of rounds to play. Odds and Evens is a point-based game, so you need to decide a game format ahead of time. Be sure to agree on a total number of rounds so you can accurately keep track of how many points each player has.^[3]
   
   • For instance, if you’d like to play a longer game, have the game be 20 rounds. A shorter game might be 3-5 rounds.
   • It may help to use a piece of scrap paper to keep track of each round.
3. Count to 3 with the other player while keeping your hands hidden. There’s no game timer in Odds and Evens, so you and the other player have to keep the game going. As you count, pick a number of fingers between 1 and 5 to hold out in your hand, which you can display after counting to 3. Make sure your hands are hidden so your opponent can’t see what number you’re holding up.^[4]
   
   • You don’t have to yell out a guess while playing Odds and Evens, but this can add a fun dimension to the game.
4. Hold up a random number of fingers on 1 hand. Reveal your hand to show how many fingers you’re holding up. You can’t change your number after counting to 3 and yelling a guess, so be really certain before holding out your hand.^[5]
   
5. Count the total number of fingers for each player to determine the winner. Count the number of fingers both you and your opponent are holding out. If the total number is odd, then the player representing “odds” wins a point for the round. If the number is “even,” then the “evens” player wins.^[6]
   
   • For instance, if you hold out 4 fingers and the other player holds out 3 fingers, the total would be 7. In this case, the winner of the round would be the “odds” player.
   • Don’t be discouraged if you don’t win the round—there’s plenty of time to catch up!

[Edit]Scoring the Game

1. Award 1 point to the winner of each round. Use a score sheet to keep track of the overall winner for each round. Mark down 2 columns for both players, then write down the score for the round.^[7]
   
2. Give 1 point to whoever guesses the correct number. If you’re playing while yelling out the guess, add 1 point to the player’s score who accurately guesses the sum. If both players guess to correct number, then they both get a bonus point.^[8]
   
   • Players have to yell the exact sum to get the bonus point. For instance, if the total sum was 9 and a player guessed 8, then they wouldn’t get the point.
   • Don’t worry about this if you’re playing a simple version of the game that doesn’t involve verbal guessing.
3. Declare a winner after you’ve gone through the rounds. Tally up the total number of points in each column, depending on the scoring method that you used. Double-check the results, then announce if the “odds” or “evens” player won the game!^[9]
   

[Edit]Video

[Edit]Tips

• If you’re yelling out a guess for the round, you’ll probably have more luck if you shout out a higher number.^[10]
• The “odds” player usually has a better chance of winning, since “2” and “10” aren’t likely to show up in a round.^[11]

[Edit]References

[Edit]Quick Summary

1. ↑ http://www.eprisner.de/MAT109/AnalysisMorra.html
2. ↑ https://healthy.uwaterloo.ca/museum/VirtualExhibits/Brueghel/odds.html
3. ↑ https://www.quantamagazine.org/solution-to-game-theory-and-evolution-puzzle-20171208/
4. ↑ https://healthy.uwaterloo.ca/museum/VirtualExhibits/Brueghel/odds.html
5. ↑ http://www.eprisner.de/MAT109/AnalysisMorra.html
6. ↑ https://healthy.uwaterloo.ca/museum/VirtualExhibits/Brueghel/odds.html
7. ↑ http://www.eprisner.de/MAT109/AnalysisMorra.html
8. ↑ http://www.eprisner.de/MAT109/AnalysisMorra.html
9. ↑ https://www.quantamagazine.org/solution-to-game-theory-and-evolution-puzzle-20171208/
10. ↑ http://www.eprisner.de/MAT109/AnalysisMorra.html
11. ↑ https://www.quantamagazine.org/solution-to-game-theory-and-evolution-puzzle-20171208/