Daily Mail 30 Second Challenge (2 Volumes)  (English, Paperback, Lock Norman)

Ever wish you were better at mental arithmetic? Young or old, everyone can sharpen their mental maths and rejuvenate the grey matter with these incredibly simple but effective puzzles straight from the desk of the original and best 30 Second Challenge maths master. See how quickly you can work your way through each puzzle - from beginner to advanced level - and feel your mental agility improve every day. Compelling, fun and suitable for all ages and abilities, this is the ultimate brain-training tool for people on the go.