Guess My Number

Goal: Identify the secret number by asking yes-or-no questions (similar to Twenty Questions)

1. Set up the game

Decide who will be the Chooser.

The Chooser secretly picks a number and announces a range in which the number falls. For instance, “I’m thinking of a number between 1 and 100.”

2. Take turns asking yes-or-no questions to find the secret number

Players cannot ask whether a certain number is the secret one. They ask questions like these:

•  Is it higher than 20?
•  Does it have a 7 in the ones place?

Children may use paper and pencil to keep track of possibilities.  For instance, if the number is between 30 and 60 and has a 4 in it:

They revise the list after each turn. 

3. Continue taking turns until only the secret number remains

The winner is the player who first narrows the possibilities down to the secret number.

Variations

Guess My Coins (Grades 3, 4, 5, 6, 7)
The Chooser chooses a secret set of coins (such as 3 quarters, 2 dimes, and 5 pennies) and tells players the total amount of money ($1.00), but not which coins. Players ask yes-or-no questions about the number and type of coins to try to identify the secret set of coins. For instance, players might ask whether the coin set contains any dimes, or whether it contains more than 5 coins in all. Try this with U.S. coins, with a set of coins from another country, or with a set from several countries.

Calculator Guess My Number (Grades 5, 6, 7)
Players ask questions that can be answered by using a calculator. For instance:
•  Is it larger than 29 x 6?
•  Is it smaller than 1785 ÷ 5?
•  Is 75 one of its factors?

 

 

Books and Other Resources

Spunky Monkeys on Parade (Grades: K, 1, 2)
Murphy, Stuart. NY: Harper Collins, 1999.

One Hundred Hungry Ants (Grades: 3, 4)
Pinczes, Elinor. NY: Scholastic, 1997.

 

Spotlight

Our number system

Reasoning about the secret number in this game helps children learn about the number sequence, number patterns, place value, and other features of the number system. Play along with children from time to time and ask questions to help them build their skills:

Easy: Ask questions about higher and lower.

Medium:Ask questions about counting patterns, even/odd, and place value.

Hard: Ask questions involving factors, multiples.

Life Connections

Number sense: comparing numbers

Comparing numbers quickly is almost automatic for many adults. People who are familiar with the number system “just know” that a 12-year-old child is younger than a 15-year-old, that a jacket priced at $53.95 is less expensive than one priced at $55.23, that a car traveling 75 miles an hour is going faster than one traveling at only 57 miles an hour, and that page 302 comes after page 197. Children—and adults who are less familiar with numbers—need a great deal of practice in order to learn to judge quickly which number is larger.

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