Oh, by the Gods ...

[fiat_knox]

I can square any two digit number in my head.

I never used to be able to do that before.

The easiest to multiply are the numbers that end in 5: 45² = 2025, 65² = 4225.

I squared 317 just now, and came up with 100,489.

In my head.

In ten seconds.

Until just now, I have never multiplied 317 by anything, let alone itself.

...



...

I still err on occasion. I still have brainfarts when I start thinking of the magnitude of what I am doing instead of just doing it. And because I haven't had practice at this any bugger with a calculator can still beat me.

But ...

I can multiply 999,999,999,999,999,999,999 x 111,111,111,111,111,111,111 - and the result takes longer for me to write out than to calculate because I've worked it out already.

The result is

111,111,111,111,111,111,110,888,888,888,888,888,888,889

and I defy you to find a calculator with enough digits to work that one out! :0D

Comments

[thewingsofisis.livejournal.com]

The easiest to multiply are the numbers that end in 4: 45² = 2025, 65² = 4225.

Wait, what?

[fiat-knox.livejournal.com]

Yup. :) Want to know that particular secret? :D

[sandchigger.livejournal.com]

I think he (or she) was saying that both those numbers end in 5, not 4 as you wrote.

[fiat-knox.livejournal.com]

Hey, look at the big ugly spider over there! *points*

*retcon retcon retcon scribble scribble scribble*

Is that so? 0:)

[sandchigger.livejournal.com]

Ah, I see, yes. I appear to have been mistaken.

[thewingsofisis.livejournal.com]

I would love to know the secret of numbers that end in 4, but are 45 and 65. :)

[fiat-knox.livejournal.com]

Mea culpa. Consider that one of the brainfarts.

I said I could work out the math in my head. Didn't say I was any good at writing it down on paper or on screen ...