I Used to Know That: Maths
This book is available for download with iBooks on your Mac or iOS device, and with iTunes on your computer. Books can be read with iBooks on your Mac or iOS device.
Brush up on your mental arithmetic, including percentages, averages and recurring decimals or work on your trigonometry skills, from Pythagoras Theorem to triangle areas and angles. "I Used To Know That: Maths" is a fun and accessible way to re-visit all those useful tips and maths tricks that you have forgotten from your school days.