Upgrade your thinking with Mind Performance Hacks

So as I started browsing Safari, one book immediately caught my attention: Mind Performance Hacks by Ron Hale-Evans. Ron is a Yale graduate who has been "thinking a lot about thinking." His online wiki is accessible at ludism.org.

I started glancing through the table of contents and before I knew it, my eyes were glued to a title, "Hack 40. Count to a Million on Your Fingers."

Excuse me? Count to a million on fingers? Interesting.

I have added the book to my favorites.

Estimating roots
To estimate square root of a number (360000) pair the number in digits
36 00 00

and then calculate the square root of the first pair without going over.

6 n n

So we know the square root of 360000 is 6nn.

Similarly to calculate cube root or nth root, create clusters of numbers with n numbers in each segment. For instance to calculate cube root of 364000 create cluster with three digits, like

364 000

Now calculate the square root of the first cluster without going over. So our square root will be

7n
[7*7*7=343]

Traditional methods of estimating square roots.

For more tricks read the book.