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?

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 ...

Examples: (1) 475 is divisible by 25 but not by 125. (2) 465 is divisible by 5 but not by a higher power of 5. As 4 + 6 + 5 = 15, it is divisible by 3 though. (3) To check for divisibility of ...

Prime numbers, vital in mathematics and competitive exams, can be quickly identified using a systematic approach. This method involves checking divisibility by primes up to the square root of the ...

WITH respect to Mr. Burgess's letter in your issue of November 4, perhaps the following general rule for testing the divisibility of a given number by another, which I found some days ago, may be of ...

This article shows the application of divisibility to some complex problems that are used to form questions in examinations like CAT. We first show a problem and its detailed solution to clarify that ...