I believe your decimal is misplaced 1 space too far to the right. 1-in-200 is a .5% chance. but I flunked fourth grade math and pretty much checked out on the math deal afterwards, so...

.5%

Half a percent.

Half as much as your first example.

Oops, that's what I mean. See? Glad I asked.

Thanks.

Just use a calculator: 1 in 100 = 1/100 = 0.01 = 1 one-hundredth. Multiply by 100 to get percent: 0.01 * 100 = 1%

Now do the same with 1 in 200. 1 in 200 = 1/200 = 0.005 = 5 one-thousandths. (One thousand divided by five is 200, so 5 one-thousandths is one two-hundredth.) Multiply by 100 to get percent: 0.005 * 100 = 0.5%.

Or alternately, 1/100 - 1%, you know. To get 1/200 from 1/100, you multiply the denominator by two: 1/(100 * 2 ) = 1/200. Since it's the denominator, it means what we're dividing by has increased by two, or our result is divided by two.

Quick help to understand fractions. Any fraction just means multiply by the numerator (the first or top number) then divided by the denominator (the second or bottom number).

So 1 in 100 is 1/100 is "multiply by 1 and divide by 100). so what's 3/200ths of 5? Multiply 5 by 3, then divide that by 200. 5 * 3 = 15. 15/200 = (3 * 5)/( 40 * 5 ) = 3/40ths.

*attempts to read ortho's response...*

*head asplodes*

If you have a fraction with a round denominator (50, 200, 1000), you can easily figure out the percentage by comparing it to x/100. So, if you want to calculate 2/1000, start with 2/100 = 2% and since 1000 is ten times 100, divide 2% by ten, so it's .2%. If you want to calculate 2/50, start with 2/100 = 2% and since 50 is half of 100, multiple 2% by 2, so it's 4% (or divide by 1/2 to keep the language consistent). That's how I think of it.

*tries babelfish on orthogonality's comment, to no avail*

What language is that? It looks Greek to me. I wish I could say it's because I'm a "word person", but it's not, I'm just dumb.

Imagine you have a monkey. And you cut the monkey into 100 pieces. And then you cut one of the pieces of the monkey into half and you put it into your mouth. And you chew on that piece of monkey for a while. Then you ask the hacked up remains of the monkey what percentage of it you're eating. And it doesn't answer you because YOU JUST KILLED THE MONKEY AND NOW YOU'RE EATING IT YOU FREAKY MONKEY KILLING MATHS FREAK.

Which is why you should never do maths. With monkeys. But mainly, you should never do any maths.

Ok, I speak as someone who had a hard time with fractions. But in 7th grade or so, the "New Math" text explained that a fraction is just multiplication and division.

And that makes it real easy.

The first number is multiplication, the second is division.

So what's 2/3 of 9? 9 times 2 divided by 3. 9 times 2 is 18. 18 divided by 3 is 6. So 6 is 2/3 of 9.

So what's 5/3 of 60? 5 times 60 = 300, divided by 3 = 100. So 5/3rds of 60 is 100.

See? Easy!

A percent is just a hundredth. The bottom part of the fraction is 100, the top part is the percentage ("Percent" = "per cent", cent is from the Latin for one hundred, so "part per one hundred.)

So what's 1% of 500?. 1% = 1/100. 1/100 of 500 is 500 times 1 divided by 100. 500 divided by 100 is 5. So 1% of 500 is 5.

I understand all the individual symbols in your comment but, when you put them together in that order, they just don't make sense.

mmmmm... beeer!!

/homer simpson mode

I'm probably going to give orthogonality hives with this, but here's how my math-incapable brain handles it: cheating.

When you take X into Y, and then mess around with Y while leaving X the same, the result changes inversely to the amount that you increase or decrease Y.

That is, if Y gets twice as big while X stays the same, then the original result becomes /half/ as big. If you multiply Y by 1.325, divide your original result by 1.325. Etcetera.

X is 1
Y is originally 100
The result is 10, or 10%.

Now we make Y 130. That's 1.3 * Y.
Divide 10 by 1.3, and you get 7.69, or 7.69%.

Now we make Y 200. That's 2 * Y.
Divide 10 by 2, and you get 5, or 5%.

Oh, for Christ's sake.

I'm a decimal point off on everything. Should be 1%, 0.769%, 0.5%, etcetera.

It's been a long day, and I'm tired, and none of you are allowed to make fun of me because I have to count on my fingers.

You know, if I tilt my head sideways, and squint really hard, I almost understand ortho's last explanation.

That's the closest I've come to understanding math in a great while. Wanna be my math tutor?

Actually, I wouldn't mind tutoring willing students. The only problem is my math skills aren't that good when I get beyond algebra. (I'd love to tutor in SQL or C++ programming.)

But honestly, it's a real joy to understand this stuff; I'm basically doing what scrump's doing. Note that scrump's discovered how the system works, how this affects that, whether he calls it math or not.

Math as it's usually taught in grade school, sucks, because it explains what to do, not how to look at the problem and really see it.

Yeah, orthogonality has it. People are often "bad at math" because they never really had the opportunity to play with it. Hey ortho, you cover everything up to algebra, and I can cover calculus and up. Now we just need someone who's an ace at trig and geometry...

Actually, I'd be game to do this. (Years ago I posted something about this on Slashdot). I could use a calc refresher, although much of my problem is forgetting trig ratios.

Geometry? Read Euclid. Seriously.

(Also, I want someone to tutor me on snazzy, Good-Time-Charlie math, like drawing to inside straights, taking walking tours of bridges, evenly dividing delicious pizzas and fixing democracy.)

I always had a real love for geometry and trigonometry. never got a chance to explore it past high school though.

...on preview, guess I'll check out Euclid. thanks!

reading the post, that combination of decimal notation and percentage is mighty confusing.
.05 is 5%.
.005 is ½%.

Then you ask the hacked up remains of the monkey what percentage of it you're eating. And it doesn't answer you because YOU JUST KILLED THE MONKEY AND NOW YOU'RE EATING IT YOU FREAKY MONKEY KILLING MATHS FREAK.


seanyboy made me laugh out loud!

By the way, ortho, your fraction explanation was awesome. Fractions have been my Waterloo for decades, and your explanation was the clearest I've ever seen for figuring out what (fraction) of (number) is.

In re: the tutoring thing, it strikes me that this would be an awesome Project. Doesn't have to be limited to math, either: I'd be happy to tutor on anatomy and physiology, pharmacology, English writing/lit, etc.

*musing*

*math major wanders into thread late, looks around forlornly, slumps shoulders, slinks away*