These 500 puzzles offer the ultimate challenge for solvers who want to pit their wits against crafty conundrums, stretch their mental powers, and sharpen their IQs. The degree of difficulty keeps rising in each of the 20 sections, so work through them in methodical order to find mathematical patterns that seem to reoccur and visual clues that overlap. That helps, as the problems get harder, but beware: just when you think you're caught on to the trick, it changes. A chain of numbers is missing one link; figure out what ...

IQ Puzzles 2007, Arcturus Publishing Ltd, London

ISBN-13: 9781841938165

Paperback

Select
IQ Puzzles 2003, Sterling Publishing (NY), London

ISBN-13: 9781402709630

Trade paperback

Select
IQ Puzzles 1999, Arcturus Publishing Ltd, London

ISBN-13: 9781900032292

Paperback

Select