## Elastic Numbers

It’s here! My new book of puzzles Elastic Numbers is now available on Amazon.

https://www.amazon.co.uk/Elastic-Numbers-Puzzles-Serious-Problem/dp/0995782601

https://www.amazon.com/gp/aw/d/0995782601

I hope you enjoy solving the problems as much as I enjoyed creating them.

## The Vault: Powers of two

My new book of maths puzzles is on its way! It’s packed full of interesting problems to sink your teeth into. I’ll post an update as the launch approaches.

In the meantime, here is a fantastic problem from the USA:

It is given that $2^{2004}$ is a 604-digit number beginning with a 1. How many of the numbers $2^0, 2^1, 2^2, 2^3, ..., 2^{2003}$ begin with a 4?

## A Game of Stones

A PuzzleCritic Original:

There are 999 stones in a pile. Amisi and Boaz take it in turns removing either 3 or 5 stones from the pile, with Amisi going first, until no more moves are possible. The last player to make a move wins. Which player can guarantee victory?

## L’s on a square

Happy New Year! From the 2004 Georg Mohr Contest:

Find all positive integers n such that a 2n x 2n chessboard can be covered by non-overlapping L-pieces, each covering 4 squares. Rotations and reflections are allowed.

## Shares

From the 2004 Tournament of Towns:

Each day, the price of the shares of the corporation “Soap Bubble, Limited” either increases or decreases by n%, where n is an integer such that 0<n<100. The price is calculated with unlimited precision. Does there exist an n for which the price can take the same value twice?