Shopping Cart
You're getting the VIP treatment!
With the purchase of Kobo VIP Membership, you're getting 10% off and 2x Kobo Super Points on eligible items.
itemsitem
With the purchase of Kobo VIP Membership, you're getting 10% off and 2x Kobo Super Points on eligible items.
Save $1.30 (13% off) and earn Kobo Super Points!
You'll see how many points you'll earn before checking out. We'll award them after completing your purchase.
Or, get it for 4800 Kobo Super Points!
See if you have enough points for this eBook. Sign in
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.
You can read this item using any of the following Kobo apps and devices: