Broaden your logic skills and identify the difficulty level right for you with a total of forty new Sudoku-by5, Sudoku-Xtreme, Education-Xtreme, HyperSudoku-by5

Broaden your logic skills and identify the difficulty level right for you with a total of one hundred five new Sudoku-by5, Sudoku-Xtreme, Education-Xtreme, Hype

This is not really a book. This is a building in the shape of a book...a maze. Each numbered page depicts a room in the maze. Tempted? Test your wits against mi

Thinking Skills, second edition, is the only endorsed book offering complete coverage of the Cambridge International AS and A Level syllabus.

The Kepler conjecture, one of geometry's oldest unsolved problems, was formulated in 1611 by Johannes Kepler and mentioned by Hilbert in his famous 1900 problem