Mind Exercise: Number Series

Mental exercise sharpens memory and delays the onset of age related mental disorders. Mind gymnastics are also fun and make great conversation starters.

Sharpen your mind and exercise your brain with this number series mind puzzle. Mind and mental exercises such as this mind teaser help to keep your brain young.

Sign up for RSS notification at the bottom of this page to be notified of new entries in the discussion thread. Click the orange icon by "how to subscribe to feeds."

Exercise:

Examine the following series of numbers and replace the question mark with the correct number:

0,3,9,18,21,27,36,?

Source: The Complete Book of Fun Maths, Philip Carter & Ken Russell

Solution here