You may also like

problem icon

Strange Numbers

All strange numbers are prime. Every one digit prime number is strange and a number of two or more digits is strange if and only if so are the two numbers obtained from it by omitting either its first or its last digit. Find all strange numbers.

problem icon


Can you find a relationship between the number of dots on the circle and the number of steps that will ensure that all points are hit?

problem icon

Factor Trio

Weekly Problem 45 - 2013
Which of the numbers shown is the product of exactly 3 distinct prime factors?