Go Pro!

Problems > High School Math > 2003

Strange Sum

Let A1776 be the set { 1, 1/2, 1/3, ..., 1/1776 }


Remove any two elements, say a and b, from A1776, and replace them with the single number ab+a+b to form set A1775.
Continue in this manner, until you have performed 1775 such operations, to form set A1, which contains a single element.



What is this element?



Prove it!


View the solution
Oh, You Can't Be Serious!
A Little Number Theory to Begin the School Year

Understanding Coronavirus Spread

A Question and Answer session with Professor Puzzler about the math behind infection spread.

Blogs on This Site

Reviews and book lists - books we love!
The site administrator fields questions from visitors.
Like us on Facebook to get updates about new resources
Pro Membership