How do you play Odds and Evens?

Odds and Evens is a two-player game. The rules are simple:

Who picks odd or even

There are several ways to assign the choice. The most common: the same player picks each round, alternating between odd and even whenever they want. In other variants, players take turns having the "power to choose" each round. On handgames.app, the system assigns the choice at the start of each round.

Example round

Player A secretly picks "even". Player A shows 3 fingers. Player B shows 2 fingers. Total = 3 + 2 = 5. 5 is odd → Player A loses the round.

Second round: A picks "odd". A shows 4 fingers. B shows 1 finger. Total = 5. 5 is odd → Player A wins.

Note: showing 0 fingers (a closed fist) is valid. A total of 0+0=0 is even — whoever picked "even" wins that round.

History: from Rome to the world

Ancient Rome: ludere par impar

The Roman poet Ovid mentions the game in Ars Amatoria (around 1 AD) as one of the pastimes of Roman youth. He called it ludere par impar — "to play odd or even" — and described it as a betting game between friends.

For the Romans, it was a game for children and adults alike. Children played it in the street; adults bet on it during festivals. The poet Horace also mentions it in his Satires, confirming it was known throughout Italy in the early common era.

Classical Greece

The Greeks had an equivalent version called Artiasmos (from artios, "even"). It was played with coins or pebbles in a closed palm, guessing odd or even — a variant without finger-counting but with the same logical structure. It was a typical pastime at Greek symposiums.

Asia and the Pacific

In Japan there's a version called Chifurechifure, or simply Kichi, played in schools. China has regional variants. In India, Satta and similar games use the same odd/even structure. The universality of the mathematical concept of parity means this game appears independently in cultures with no direct contact.

Latin America

In Argentina, Uruguay and Chile the game is known as "par o impar" and is part of the childhood of generations. It's used to decide who goes first in other games, who pays for something, or simply as a game in itself. In Brazil it's called par ou ímpar and is just as popular — often accompanied by a rhythmic count of "one, two, three, go!"

What it's called in other countries

Strategy: is there a way to win more?

Odds and Evens has more of a luck component than Chopsticks or Morra — but it isn't fully random against humans.

The middle-number bias

Players tend to show 2 or 3 fingers more often than 0, 1, 4 or 5. The extremes feel "weird" or predictable. This has implications for your strategy: if you want to control the parity of the total, showing 2 (even) or 3 (odd) gives you more control than the extremes, because you can better anticipate the range of what your opponent will show.

Influencing the total with your own fingers

If you think your opponent will show 3 fingers (odd), and you picked "even": you need the total to be even. To do that, show an odd number (1, 3 or 5) — odd + odd = even. If you think they'll show 2 (even) and you picked "odd": show an odd number too — even + odd = odd. The parity table is simple:

Watching for patterns

If your opponent has shown 2 fingers for the last three rounds in a row, they're probably about to switch. If they never show 5, you know the maximum range for the total is 4 plus something between 0 and 4. Every observation reduces the uncertainty.

Odds and Evens as a teaching tool

Odds and Evens is ideal for teaching the concept of odd and even numbers to kids aged 5 to 8. Adding two numbers and determining parity becomes concrete and meaningful when there's a "win or lose" outcome attached. It's one of the most recommended activities by elementary math teachers for introducing arithmetic in a playful way.

If you're looking for more no-materials games for the classroom, you might also like Chopsticks (addition and strategy) and Morra (fast addition from 2 to 10).

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