Prove that the equation \(x^2 + 4034 = y^2\) does not have solutions in integer numbers.
Find a solution of the equation \(x^2 + 2017 = y^2\) in integer numbers.
Alice marked several points on a line. Then she put more points – one point between each two adjacent points. Show that the total number of points on the line is always odd.
The date 21.02.2012 reads the same forwards and backwords (such numbers are called palindromes). Are there any more palindrome dates in the twenty first centuary?
Do there exist three natural numbers such that neither of them divide each other, but each number divides the product of the other two?
Find all the solutions of the puzzle and prove there are no others. Different letters denote different digits, while the same letters correspond to the same digits. \[M+MEEE=BOOO.\]
Is it possible to arrange some group of distinct numbers in a circle so that each number equals the sum of its neighbours?
Sarah is writing down natural numbers starting from 2. She notices that each time she writes the next number the sum of all written numbers is less than their product. She believes she can find such 57 natural numbers (not necessarily different from each other) that their sum will be greater than their product. Do you think it is possible?
(a) Can you find a set of distinct numbers which can be arranged in a circle in such a way that each number equals the product of its neighbours?
(b) Is it true that each solution of Example 1 is determined by the values of two neighbouring numbers?
It’s not that difficult to find a set of \(57\) integers which has a product strictly larger or strictly smaller than their sum. Is it possible to find \(57\) integers (not necessarily distinct) with their sum being equal to their product?