SKIRMISHER

You can get rid yourself of an extra load by having a “built-in” calculator right inside your head:

1. Round Off to a Quick Approximation

First determine a level of accuracy you are happy with, then round the numbers appropriately before making the calculation. This is also useful to determine a quick ballpark figure before doing the actual calculation.

2. Break Up Into Parts

Say you have to multiply 613 by three. Try multiplying first 600 by 3, then 10 by 3 then 3 by 3 and adding the results.

Read the rest here and amaze your friends with your newfound mathematical magic. Then invite them to a grocery nearest you; you’ll do the fast calculating, they’ll do the fast paying. But that’s one technique that you’d have to learn for yourself.

Stumble it!