I closed my recent post, So Long, Long Division, by asking you to either join me in acknowledging that long division is a meaningless math procedure or to share reasons students should learn long ...

It’s easy to tell if a given whole number is divisible by 2. Just check whether the last digit is even. There are also simple rules to determine whether a number is ...

The crisp new dollar bill that I have just taken from my wallet bears the serial number 24598176. It’s easy to tell that the number is exactly divisible by 2 but not by 5. Is it divisible by 3? by 4?

From Quanta Magazine (find original story here). Two young computer scientists have figured out how to fairly divide cake among any number of people, setting to rest a problem mathematicians have ...