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2, 3, and every integer of the form 6n +/- 1 up to the square root of the number, rounded up. This is the simplest way to check a smaller subset of possible divisors, and yet not worry about the primality of the divisors.

Q: What do divide a number by to see if its prime?

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You divide the number by 2. If the number is able to divide WITHOUT a remainder, then it is a prime number. If you divide a number by 1, you will get the same number. That is not a prime number.

Yes. To prove it, you can take the square root of 2011 (about 44.8), and divide 2011 by all the prime numbers under this number. You'll see none of them divide, so it's prime.

120 is NOT a prime number because you can divide it by 10 and 5 and 2....

No it is not. A prime number will only divide (to give an integer as a result) by 1 and itself. 267 will also divide by 89 & 3 so it is not prime.

Well if you make a tree you'll get these answers!! 88 divided by 2 equals 44 and divide that by two you get 22 and divide that by 2 you get 11 and then you get divide it anymore!! So the prime number would be 11 of the number 88. Or you could've just divided by 8 to see what you get. =) 11 is the answer. The work is shown above for your convenience.

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You divide the number by 2. If the number is able to divide WITHOUT a remainder, then it is a prime number. If you divide a number by 1, you will get the same number. That is not a prime number.

The prime number 3 can divide 27 and 36.

Divide the prime number.

Yes. To prove it, you can take the square root of 2011 (about 44.8), and divide 2011 by all the prime numbers under this number. You'll see none of them divide, so it's prime.

The smallest prime number that will divide 147 evenly is three.

There are only 9 numbers between 80 and 90 - so lets look at them all Remember we only need to find 1 number that will divide the number except for 1 and itself for it to be NON-PRIME. 81 - 3 will of course divide this number - so not prime. 82 - 2 will of course divide this number - so not prime. 83 - PRIME!!! 84 - 3 will of course divide this number - so not prime. 85 - 5 will of course divide this number - so not prime. 86 - 2 will of course divide this number - so not prime. 87 - 3 will of course divide this number - so not prime. 88 - 2 will of course divide this number - so not prime. 89 - PRIME!!! So, the only numbers between 80 and 90 that are primes are 83 and 89!

It isn't 1 is. 1 is always the smallest. Can you divide 1 and get a whole number? No a prime number is something that you can divide into, yes you can divide it, making it a negative number, but not a whole number. * * * * * In fact, 1 is NOT a prime (nor a composite), so 2 IS the smallest prime.

120 is NOT a prime number because you can divide it by 10 and 5 and 2....

No it is not. A prime number will only divide (to give an integer as a result) by 1 and itself. 267 will also divide by 89 & 3 so it is not prime.

A prime number can only be divided evenly by one or by itself.

I THINK... you see if it can be either multiplied or divided by any other number but 1, and if you can divide or multiply by any other number it is composite, if it cant be divided or multiplied, it is prime...

The prime numbers are: 5 and 43