You may also like

problem icon

Converging Product

In the limit you get the sum of an infinite geometric series. What about an infinite product (1+x)(1+x^2)(1+x^4)... ?

problem icon

Circles Ad Infinitum

A circle is inscribed in an equilateral triangle. Smaller circles touch it and the sides of the triangle, the process continuing indefinitely. What is the sum of the areas of all the circles?

problem icon

Binary Squares

If a number N is expressed in binary by using only 'ones,' what can you say about its square (in binary)?

Sixty-seven Squared

Stage: 5 Challenge Level: Challenge Level:1
Lots of sixes followed by a seven can be written as a sum of a series involving powers of 10.