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?

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 ...

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 ...