Problem of the Week

A new problem every Monday that challenges participants of all ages to think creatively and apply their math skills. Perfect for a weekly mental challenge.

Let abc be a 3-digit positive integer. Find the number of such integers where ab, bc, and abc are all prime numbers.  For example, 373 is a prime number and 37 and 73 are also prime numbers. Therefore 373 is one of these three-digit numbers.

 


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