Active Math Game: Rock

Gordon Hamilton of Math Pickle posted Rock, a new active math game for grades K–2. If you have a set of kids and a few minutes to spare, give it a try!

How to Play Rock

  • Everyone makes a rock shape with eyes closed.
  • Everyone chooses a number: 0, 1, 2, 3, 4, 5, 6, 7, 8 …
  • Teacher calls out numbers consecutively, starting at 0.
  • When a student hears their number being called they immediately raise a hand. When the teacher tags the hand, they stand up.
  • If more than one hand was raised, those students lose. They become your helpers, tagging raised hands.
  • If only one hand was raised, that child wins the round.


“Each game takes about 45 seconds,” Hamilton says. “This is part of the key to its success. Children who have not learned the art of losing are quickly thrown into another game before they have a chance to get sad.”

The experience of mathematics should be profound and beautiful. Too much of the regular K-12 mathematics experience is trite and true. Children deserve tough, beautiful puzzles.

Gordon Hamilton

What Happens When Grownups Play Rock

What are the best numbers to pick? Patrick Vennebush hosted on online version of the game at his Math Jokes 4 Mathy Folks blog a few years back, though we didn’t have to bend over into rocks‌—‌which is a good thing for some of us older folks.

Vennebush also posted a finger-game version suitable for small groups of all ages, called Low-Sham-Bo:

  • On the count of 1-2-3, each person “throws” out a hand showing any number of fingers from zero to five.
  • The winner is the person who throws the smallest unique number.

You may want to count “Ready, set, go!” for throwing out fingers, so the numbers in the count don’t influence the play.

The official name for this sort of game is Lowest Unique Bid Auction.

Free-Learning-Guide-Booklets2Claim your two free learning guide booklets, and be one of the first to hear about new books, revisions, and sales or other promotions.

New Hundred Chart Game: Odd-Even-Prime Race


100chart[Photo by geishaboy500 (CC BY 2.0).]

Counting all the fractional variations, my massive blog post 30+ Things to Do with a Hundred Chart now offers nearly forty ideas for playing around with numbers from preschool to prealgebra.

Here is the newest entry, a variation on #10, the “Race to 100” game:

(11.5) Play “Odd-‌Even-‌Prime Race.″ Roll two dice. If your token is starting on an odd number, move that many spaces forward. From an even number (except 2), move backward — but never lower than the first square. If you are starting on a prime number (including 2), you may choose to either add or multiply the dice and move that many spaces forward. The first person to reach or pass 100 wins the game.
[Hat tip: Ali Adams in a comment on another post.]

And here’s a question for your students:

  • If you’re sitting on a prime number, wouldn’t you always want to multiply the dice to move farther up the board? Doesn’t multiplying always make the number bigger?

Free-Learning-Guide-Booklets2Claim your two free learning guide booklets, and be one of the first to hear about new books, revisions, and sales or other promotions.

Review Game: Once Through the Deck

Ace of Spades

[Feature photo above by Shannon (shikiro famu) via Flicker (CC BY 2.0).]

Math Concepts: basic facts of addition, multiplication.
Players: one.
Equipment: one deck of math cards (poker- or bridge-style playing cards with the face cards and jokers removed).

The best way to practice the math facts is through the give-and-take of conversation, orally quizzing each other and talking about how you might figure the answers out. But occasionally your child may want a simple, solitaire method for review.

Continue reading Review Game: Once Through the Deck

Math Game: Fan Tan (Sevens)


Feature photo above by Morgan (meddygarnet) via Flicker (CC BY 2.0).

Math Concepts: sorting by attribute (card suits), counting up, counting down, standard rank of playing cards (aces low).
Players: two or more, best with four to six.
Equipment: one complete deck of cards (including face cards), or a double deck for more than six players. Provide a card holder for young children.

How to Play

Deal out all the cards, even if some players get more than others. The player to the dealer’s left begins by playing a seven of any suit. If that player does not have a seven, then the play passes left to the first player who does.

After that, on your turn you may lay down another seven or play on the cards that are already down. If you cannot play, say, “Pass.”

Once a seven is played in any suit, the six and the eight of that suit may be played on either side of it, forming the fan. Then the five through ace can go on the six in counting-down order, and the nine through king can go on the eight, counting up. You can arrange these cards to overlap each other so the cards below are visible, or you can square up the stacks so only the top card is seen.

A Fan Tan game in progress.
A Fan Tan game in progress.

Continue reading Math Game: Fan Tan (Sevens)

Math Games with Factors, Multiples, and Prime Numbers

factor game

Students can explore prime and non-prime numbers with two free favorite classroom games: The Factor Game (pdf lesson download) or Tax Collector. For $15-20 you can buy a downloadable file of the beautiful, colorful, mathematical board game Prime Climb. Or try the following game by retired Canadian math professor Jerry Ameis:

Factor Finding Game


Math Concepts: multiples, factors, composite numbers, and primes.
Players: only two.
Equipment: pair of 6-sided dice, 10 squares each of two different colors construction paper, and the game board (click the image to print it, or copy by hand).

On your turn, roll the dice and make a 2-digit number. Use one of your colored squares to mark a position on the game board. You can only mark one square per turn.

  • If your 2-digit number is prime, cover a PRIME square.
  • If any of the numbers showing are factors of your 2-digit number, cover one of them.
  • BUT if there’s no square available that matches your number, you lose your turn.

The first player to get three squares in a row (horizontal, vertical, or diagonal) wins. Or for a harder challenge, try for four in a row.

Feature photo at top of post by Jimmie via flickr (CC BY 2.0). This game was featured in the Math Teachers At Play (MTaP) math education blog carnival: MTaP #79. Hat tip: Jimmie Lanley.

Free-Learning-Guide-Booklets2Claim your two free learning guide booklets, and be one of the first to hear about new books, revisions, and sales or other promotions.

Math Game: Thirty-One

Canterbury Puzzles

Math Concepts: addition to thirty-one, thinking ahead.
Players: best for two.
Equipment: one deck of math cards.

How to Play

Lay out the ace to six of each suit in a row, face up and not overlapping, one suit above another. You will have one column of four aces, a column of four twos, and so on‌—‌six columns in all.

The first player flips a card upside down and says its number value. Players alternate, each time turning down one card, mentally adding its value to the running total, and saying the new sum out loud. The player who exactly reaches thirty-one, or who forces the next player to go over that sum, wins the game.


Continue reading Math Game: Thirty-One

Math Game: Chopsticks


Feature photo above by Harry (Phineas H) via Flicker (CC BY 2.0).

Math Concepts: counting up to five, thinking ahead.
Players: two or more.
Equipment: none.

How to Play

Each player starts with both hands as fists, palm down, pointer fingers extended to show one point for each hand. On your turn, use one of your fingers to tap one hand:

  • If you tap an opponent’s hand, that person must extend as many extra fingers on that hand (in addition to the points already there) as you have showing on the hand that tapped. Your own fingers don’t change.
  • If you force your opponent to extend all the fingers and thumb on one hand, that makes a “dead hand” that must be put behind the player’s back, out of the game.
  • If you tap your own hand, you can “split” fingers from one hand to the other. For instance, if you have three points on one hand and only one on the other, you may tap hands to rearrange them, putting out two fingers on each hand. Splits do not have to end up even, but each hand must end up with at least one point (and less than five, of course).
  • You may even revive a dead hand if you have enough fingers on your other hand to split. A dead hand has lost all its points, so it starts at zero. When you tap it, you can share out the points from your other hand as you wish.

The last player with a live hand wins the game.

When a two-points hand taps a one-point hand, that player must put out two more fingers.
When a two-points hand taps a one-point hand, that player must put out two more fingers.

Continue reading Math Game: Chopsticks