Let’s define a function over the non-negative integers in the following manner: P(n) = n when n is a one-digit integer. P(n) = the product of all the digits of n when n > 9. Example: P(1729) = 126, because 1 × 7 × 2 × 9 = 126. Evaluate the following: Note: this problem was shared to [...]
While taking a coffee break, my secretary, Sue, happened to glance at her digital watch. It showed the following time: 1 : 4 4 “That’s rather curious,” she thought. “If I remove the two dots, I’ll have the number 144, which is the square of 12. I wonder how likely that sort of thing happens [...]
No, that is not someone’s telephone number up there in the title of this piece. It is the name of a numerical puzzle guaranteed to spark wonder and amazement in the minds of your students. It is called Kaprekar’s (pronounced kuh-PREE-kur) Constant*. This little, mysterious math activity is one of a family of math procedures called [...]
INTRODUCTION A. When a number is multiplied by itself, the resulting product is called a SQUARE NUMBER, or simply a SQUARE. 12 × 12 = 144 so 144 is a square number. 35 × 35 = 1225 so 1225 is a square number. 133 × 133 = 17,689 so 17689 is a square number. B. [...]
Background In the latter part of May of this year (2001) we discovered a very interesting website all about prime numbers, titled appropriately The Prime Pages. There is a companion page connected with it, called Prime Curios, a collection of clever and interesting trivia, moderated by G. L. Honaker, Jr. It is to this 2nd [...]
This is a math activity that needs you to use your best investigation skills. So get out your paper and pencil and put on your thinking cap. (And you may wish to consider a calculator, but it won’t be of much use some times.) Definition Let a rep-digit number be any number that consists of a [...]
A Digital Diversion Perform the following steps as indicated to see an interesting result. Form the smallest possible 4-place number using the four largest digits. Add that number to itself. The result is sum #1. Take sum #1 and add it to itself. The result is sum #2. Finally, take sum #2 and add it [...]