Friday, July 15, 2011

Math Games

Here are a few math games you can try..using only dice or a deck of playing cards or number cards (1-10). (At our local dollar store you can get a 2 pack of playing cards for $1.) For most games, remove the face cards. (OR you can keep them in and decide their value in advance...such as Ace = 1, Jack =10, Q = 11 and K = 12).

War: Remove the face cards (or keep them in and make A =1, J, Q, and K = 10 or 10, 11, and 12) Divide the cards into 2 piles. Each person flips over top card and the person with the highest card wins and takes both cards. If there is a tie, then flip over next card and winner of that round takes all 4 cards. I make the child say, "8 is greater than 4" to practice math language. Player with most cards at the end, wins.

Variations on war:
Peace: The same as war, but the lowest card wins. "6 is less than 9."

Addition War: Each person flips over 2 cards and adds them together...the highest total wins (or the lowest total...your choice...just set the rules at the beginning.)

Subtraction War: Each person flips over 2 cards and subtracts them...the highest difference wins. (Or lowest difference.)

Multiplication War: Flip over 2 cards and multiply. Highest product wins.

Fraction War: Flip over two cards and make a fraction... 2 and 5 can be 2/5 or 5/2... Highest fraction wins. (You can set the rules that the fraction has to be smaller than one so that only 2/5 will work for younger players.) This is challenging...not only are they making a fraction but comparing fractions with different denominators...for most kids this might not be appropriate until around fourth grade.

Concentration: Put part (or all) of the deck of cards spread apart on a table or floor face down. Then flip two cards over and if they are a match, you keep them. If not flip back over and the other person takes a turn. YOu can also do Make Ten Concentration where the two cards have to add up to 10 in order for you to keep them.

Salute: This is a game for 3 players. Two players are dealt the deck of cards, and they sit facing each other. The third player sits where they can see both of the other players. Third player says, "Salute". Then the two players with cards pick up the top card of their deck, without looking and put it on their forehead (so they can't see it but the other person can). Then the third person tells what the sum (for addition) or product (for multiplication) is. Each person tries to figure out what his/her number is...the first person to do so, gets both cards. Player with most cards at end wins.

Lamborghini Game: (or Highest Number Possible)... Play this by writing blank lines on a paper...3 lines if you want to go the hundreds place, 5 lines if you want to go to the ten thousands place, etc. ____ ____ _____. The child is trying to beat the adult and win the "lamborghini" (a hot wheels car). Flip over a card. Each of you must decide on which line to put that number. For example, if you get a 6, you might decide that you will get a higher number later and put it on the tens place. But maybe your child puts it in the hundreds place. then flip over another card... and place it on a line. Keep playing until all lines are filled...then compare your number...if they are lower than you or tied with you, they don't get the keep it. But if they beat you, they keep it. Play several rounds. The first time or two that you play this, you might reason out loud why you are doing what you are doing. "Oh, I got a 2. That's a small number so I'm going to put it in the ones place." "Now I got a seven. That's a pretty big number...I could still get an 8 or 9, but I don't think I will, so I'll put it on the hundreds place." This game requires both luck and skill so your child has a good chance of beating you once they understand place value.

Top Dog: Divide deck of cards into 2 piles. Each person flips over 3 cards and uses two of them to make the biggest number possible, discarding one card. (With 2, 6, and'd make 96 and discard the 2 at the bottom of their pile). The person with the highest number is the top dog and takes all the cards. Keep playing until all cards have been used. Person with the most cards at the end is the TOP DOG. You can also draw 4 cards and make the biggest 3 digit number or take 5 cards and make the biggest 4 digit number.

Close to 20:
Remove the kings and jacks from a deck of cards. In this game Aces are one and Queens are zero. The object of the game is to make an addition problem with three addends as close to 20 as possible (see the sample game board below). Each game has five rounds. To play deal out five cards and place them so all players can see them. Each player uses the numbers on any three of the cards to make a total that is as close to 20 as possible; you may use each card only once. The player writes the numbers they chose and total on their score sheets. The points for each round is the difference between the sum and 20 (for example a sum of 24 scores 4 points and so does a sum of 16). Put all five cards in a discard pile and deal out five more for the next round. After five rounds, players total their points and the player with the
lowest score wins.
Score sheet:
Round 1: _________ + _________ + __________ = __________ __________pts
Round 2: _________ + _________ + __________ = __________ __________pts
Round 3: _________ + _________ + __________ = __________ __________pts
Round 4: _________ + _________ + __________ = __________ __________pts
Round 5: _________ + _________ + __________ = __________ __________pts

Variations: Play close to 25 by dealing 6 cards and choosing 4 to add. Play close to 10 by dealing only 3 cards and choosing 2 to add. Or make it harder and play close to 100. Divide the deck in half and each round, each player draws four cards. THey use four of the cards to make 2 two digit numbers that are as close to 100 as possible. Then the points are the difference between their number and 100. (For example, if you draw 2, 7, 3, 9, and 6... you might do 72 + 36 = 108 which gives you 8 points. Or you might do 67 + 32 = 99 which gives you 1 point.) The person with the lowest score at the end wins.

Guess My Number: The child or parent draws 2 cards and uses them to make a two digit number. The other person then must ask questions to try to guess the number. The questions must use math vocabulary, such as: Is it even? Is it greater than 50? If you add the two digits together, is the sum 5? Is it divisible by 3? *Note: This game can be played with multiple players. It can be made harder or easier depending on the age of the child by using smaller or bigger numbers. And you can play without a deck of cards...just think of a number and have the other player(s) try to guess the number.

Go Fish: Each player is given 7 cards, then the rest are put in a pile to draw from. First player asks if the other player has a certain number. If they do, they give it to the first player and the player lays the match down. If not, they say, "Go fish" and the player draws a card from the pile. Variation: Make this more difficult by doing Go Fish +1... The child must ask for a number that is one more than a card in their hand. For example, if they have a 5, then they ask for a 6. If they get it, then they say 5 + 1 =6 and put it down. Play continues until all cards are used. Player with the most matches wins. (You could also do Go Fish +2 or Go Fish +3 to practice those math same way as Go Fish +1, but add two or add three instead.)

Games Using Dice:

Pig: The goal of Pig is to be the first player to get to 100. The game is played with a pair of dice, and requires a paper and pencil for scoring.
1. The first player rolls the dice, calculates the sum (mentally), then rolls again if he or she wants to. The next sum is added to the first. The player can roll as often as s/he wants to before play goes to the next turn. However...
2. If a 1 comes up on one of the dice before the player decides to stop rolling, the player scores 0 for that round. The play goes to the next player.
3. Worse still, if a 1 comes up on both of the dice, the turn ends and the player's entire total falls to 0.

Use dice to practice probability. You can also use spinners and coins and drawing different colored objects out of a bag. Write down the numbers from 2 -12. Have the child roll two dice and record the total. Repeat about 20 times. Then talk about why some sums were more common (it's hard to get 2...the only way is to roll 1 +1...but it's easy to get 7... 1 + 6, 2 + 5, 3 + 4.) With spinners, record what is landed on and talk about whether the spinner is fair or unfair. Flip and coin and talk about what probability says should happen...and whether that is what happens. Put different objects in a bag... maybe 5 blue blocks, 3 red and 1 yellow. Reach in and pull 1 out...record what color it is and put it back in the bag. Shake the bag to mix objects and then repeat...about 20 times. Record results.

Going to Boston: This game requires three dice and pencil & paper.
In one turn, the first player rolls all three dice. The highest roll is put aside. The next two dice are rolled and the highest number is put aside again. The last dice is rolled, then all three dice are added together.
The winner is whoever gets to a predetermined amount first, such as 100.
Variations on the game are adding the first two dice and multiplying the sum by the third; using any combination of addition, subtraction, multiplication or division to get the highest number possible, or just using two dice to practice basic math facts (addition, subtraction or multiplication).

Array Arrangement: Multiplication
Using a pair of dice, the students are to draw the product on graph paper as a rectangular array.
For example, if a 4 and a 3 are rolled, that means 4 x 3 = 12. The array is drawn as 4 rows and 3 columns, to make a rectangle. Each time a square number is drawn, let the students color it in red. Label each array with the number sentence it goes with.

Many of the card games could also be played by using dice in place of the cards.

See, I told you...math is fun!!!