# How to mentaly get answers at once when given in powers?

1. Apr 23, 2006

### dilan

Is there any method that you can calculate by mentaly and get answers mentaly when a number is given with a power.
I mean for example say, 3^4 will be equal to 81. This is just a simple one. I mean now if a number is given like 6^12 then is there a method that you can get the answer by mental caculation ?

Thank you.

2. Apr 23, 2006

### mathman

This seems to more of a problem in brain function than math. Essentially, how adept are you at multiplying large numbers mentally (I am assuming that you have not memorized a table of logs)? For your example, 6^2=36, 36^2=pa, pa^3=pb. If you can do it, more power to you!

3. Apr 24, 2006

### Nimz

You can sort of cut corners in the process if you memorize powers of numbers. E.g. 63=216. 64=1296. 65=7776. 66=46656. If you want to do mental calculations of this sort, you can make some sort of tradeoff between what you memorize and what you calculate. I have some of those memorized because I've calculated them several times :P

About 13 years ago a book was written, Dead Reckoning: Calculating Without Instruments, by Ronald W. Doerfler and Ronald E. Doerfler. If you are interested in doing this sort of thing, and more, I'd suggest you take a look at it. Here's the link to it on Amazon.

Last edited: Apr 24, 2006