LOGICVILLE
 Mathematical Puzzles Cryptarithms Anagrams Cryptograms Doublets Logic Puzzles Magic Word Squares Sudoku Chess Fractal Puzzles Tangrams

 Intellectual Puzzles Bookstore List of Puzzles Analytical Puzzles Christmas Puzzles New Year's Puzzles Fractal Puzzles Easter Puzzles Nature Fractals Encrypted Quotations Fractal Images Baseball Puzzles Daily Fractal Puzzle Math Recreations Algebra Placement Cryptogram Challenge Sudoku Tangrams Tangram Stories Puzzle Categories Thanksgiving Quotes Christmas Quotes Christmas Logic New Year Resolutions Solutions Advertise With Us

List of Puzzles

List of Solutions

Solution to Puzzle 39.  PRIME NUMBERS

Prime numbers are numbers whose only divisors are one and itself.  For example, 31 is a prime number because its only divisors are 1 and 31.  However, 12 is not a prime number because it can be divided by 1, 2, 3, 4, 6, or 12.

There are NO PRIME NUMBERS among those 9-digit numbers that can be formed by rearranging the digits in the number:

 1  2  3  4  5  6  7  8  9

Any number whose digits sum up to a number divisible by 3 is divisible by 3.  The above number has this property, and therefore any number formed by rearranging the digits of this number is divisible by 3 and therefore not a prime number.

Support this site

From Our Books Collection

 Aha! Gotcha : Paradoxes to Puzzle and Delight Author:  Martin Gardner

Custom Search