“Few people, including many mathematicians, know all the simple rules by which large numbers can be tested quickly for divisibility by numbers 1 through 12,” Gardner remarked ...

Learn how to check divisibility by 13 with Sall's Theorem! This easy-to-follow method helps you determine if a number is divisible by 13 without doing long division.

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 some interest.

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 ...

As 4 + 6 + 5 = 15, it is divisible by 3 though. (3) To check for divisibility of 8976730213 by 11, we first form the two sums: 8 + 7 + 7 + 0 + 1 (= 23) and 9 + 6 + 3 + 2 + 3 (= 23) then find the ...