Checking if a no is divisble by 24 or large nos.

• Jun 21st 2012, 11:29 AM
MikeNoob
Checking if a no is divisble by 24 or large nos.
While preparing for standardized tests i need a quick method to see if one no is divisible by another however these quick tests are only available to check for divisibility by 2,3,4,5,6,7,8,9,10 or 11. How do i check if a no is divisible by a larger no say 23 ?
• Jun 21st 2012, 12:30 PM
richard1234
Re: Checking if a no is divisble by 24 or large nos.
23's a little difficult; I don't know any easy way other than simply, divide by 23. For other numbers, say, 24, just make sure it's divisible by both 8 and 3.

You're from AZ, are you referring to the AIMS test? I hate that test...
• Jun 21st 2012, 12:43 PM
MikeNoob
Re: Checking if a no is divisble by 24 or large nos.
Naa am planning for the GRE
• Jun 21st 2012, 12:51 PM
richard1234
Re: Checking if a no is divisble by 24 or large nos.
Ah okay.
• Jun 21st 2012, 01:34 PM
Reckoner
Re: Checking if a no is divisble by 24 or large nos.
Quote:

Originally Posted by MikeNoob
While preparing for standardized tests i need a quick method to see if one no is divisible by another however these quick tests are only available to check for divisibility by 2,3,4,5,6,7,8,9,10 or 11. How do i check if a no is divisible by a larger no say 23 ?

Wikipedia has divisibility rules for larger numbers, but it probably isn't worth memorizing more than a few common ones.

For 23, add seven times the units digit to the other digits and see if you get a number divisible by 23.