A Wonderleaf question
What makes a number prime?
a real page from the book
A number is prime when the only whole numbers that divide it evenly are 1 and the number itself. So 2, 3, 5, and 7 are prime, while 4 is not, because 2 times 2 makes it exactly.
Primes are useful because bigger whole numbers can be built from them in one exact recipe. For instance, 12 breaks into 2, 2, and 3. Mathematicians still search for enormous primes, and modern secret codes use them to help protect information.
Wonder words
- prime
- composite
- factor
- divide
Try it out
Choose a number under 30 and try making it with equal rows of coins, buttons, or small snacks.
Read the whole picture book
Watercolour scenes, straight answers, about three minutes cover to cover.
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