# Thread: How long does it take you to do square root of imperfect number in your mind?

1. ## How long does it take you to do square root of imperfect number in your mind?

How long does it take you to do square root of imperfect number in your mind, without calculator, pen nor paper?

Can any one do a square root of any number up to 4 or 5 s.f. within 1 or 2 minutes, in your mind?

Just wondering what is the quickest way to do square root with mind alone

2. ## Re: How long does it take you to do square root of imperfect number in your mind?

Most numbers you square root are indefinitely long, so define how many digits you want the answer to be.

3. ## Re: How long does it take you to do square root of imperfect number in your mind?

Originally Posted by D10
How long does it take you to do square root of imperfect number in your mind, without calculator, pen nor paper?

Can any one do a square root of any number up to 4 or 5 s.f. within 1 or 2 minutes, in your mind?

Just wondering what is the quickest way to do square root with mind alone
I can't explain it well, so take a look at the third method here. It works similar to long division, but with important differences. I learned it in High School and, though there is no real need for it any more (cell phones can do square roots now!) it's a neat trick to learn. The other two methods work quickly but if you need the square root of 127 the third one is likely the one you'll need.

-Dan

4. ## Re: How long does it take you to do square root of imperfect number in your mind?

Let say 4 digits, how long does it come up with the square root of, let say "21" to its square root for 4 digits?

5. ## Re: How long does it take you to do square root of imperfect number in your mind?

Originally Posted by topsquark
I can't explain it well, so take a look at the third method here. It works similar to long division, but with important differences. I learned it in High School and, though there is no real need for it any more (cell phones can do square roots now!) it's a neat trick to learn. The other two methods work quickly but if you need the square root of 127 the third one is likely the one you'll need.

-Dan
Thanks Dan! So let say for 127, can you do the square root in your mind by the long division method?

I'm not a Math major, but I just feel fun trying to do these kind of calculations when I'm bored so I can prevent my brain from degenerating lol

6. ## Re: How long does it take you to do square root of imperfect number in your mind?

Originally Posted by D10
Thanks Dan! So let say for 127, can you do the square root in your mind by the long division method?

I'm not a Math major, but I just feel fun trying to do these kind of calculations when I'm bored so I can prevent my brain from degenerating lol
It can be done, but obviously you'll need a fair amount of practice. I used to be able to do it, but my grey cells are a bit wrinkled now.

-Dan

7. ## Re: How long does it take you to do square root of imperfect number in your mind?

Originally Posted by topsquark
It can be done, but obviously you'll need a fair amount of practice. I used to be able to do it, but my grey cells are a bit wrinkled now.

-Dan
Awesome, let me do more practice then =) Thanks!