Showing posts with label positive integers. Show all posts
Showing posts with label positive integers. Show all posts

Saturday, July 23, 2011

Smallest positive integer

What is the smallest positive integer n such that n^2 and (n + 1)^2 both contain the digit 7 but (n + 2)^2 does not

Tuesday, July 19, 2011

How many positive integers

How many positive integers x are there such that 3x has 3 digits and 4x has four digits?