Metamath Home Page. Trick 1 : Fast Math to Multiply Numbers. Erich's Packing Center. Packing Equal Copies Covering Packing Copies to Maximize Total Perimeter Tiling Other Packing Problems Animations and Rigid Packings.
Table of Contents. Nerd Paradise : Divisibility Rules for Arbitrary Divisors. It's rather obvious when a number is divisible by 2 or 5, and some of you probably know how to tell if a number is divisible by 3, but it is possible to figure out the division 'rule' for any number.
Here are the rules for 2 through 11... The last digit is divisible by 2. The sum of all the digits in the number is divisible by 3. The last 2 digits are divisible by 4. The last digit is 5 or 0. Why 5, 8 and 24 Are the Strangest Numbers in the Universe.