Maths on the Back of an Envelope
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Maths on the Back of an Envelope

Clever ways to (roughly) calculate anything

By Rob Eastaway

I've forgotten more high school maths than I care to admit so this was a great little refresher.

Some nice pointers for improving your mental arithmetic, which is always handy when you have to quickly report on numbers at work. Worth pickip up for 99p if you see it on Kindle sale like I did.

Cheers,