mathematical symbol

[Explorer-8]

What does the mathematical symbol ' mean?
For example, in an on-line quiz, one question might be 20'30'45? What does that mean?

[theprof]

This is known as the Prime Symbol. It can have different meanings depending upon the context used. Without knowing more about the question you're querying, the best I can do is provide you with the following link which should answer your question.

http://en.wikipedia.org/wiki/Prime_(symbol)

[factor-fiction]

I've never seen this symbol used with numbers on an online quiz !
The only answers I can think of are feet or possibly minutes, but to say 20 feet 30 feet 45 feet wouldn't make sense on a quiz show unless they are asking you to choose from the 3 answers.
The symbol is used in other contexts in maths but not with numbers- for example in calculus f '(x) represents the derivative of the function f(x). It's also use dto represent set complements. But agagin i can't see these being covered in a quiz.

[R1Geezer]

Looks like it probably means Degrees, Minutes, seconds when referring to an angle, Can you give us the context.

[TCL-MUMPING]

It would normally be written as 20� 30′ 45″, which is
20 degrees 30 minutes 45 seconds. There are sixty minutes in a degree and sixty seconds in a minute. In the decimal form it would be 20.5125�.

[Explorer-8]

Thanks for your replies. At least now I can learn about prime.
When I went straight from the quiz to this site, I'd made the mistake of memorising the sign upside down, so I thought it was an apostrophe. I have just had another look at the quiz and one of the actual questions was 15,16 x 2,31. So it was a comma not an apostrophe. I'm sorry about my mistake. What does the comma mean here?

[rojash]

Well, if the site was European, it's probably a decimal point.

[rojash]

See here:
http://mathworld.wolfram.com/DecimalPoint.html

[Explorer-8]

That's interesting and helpful too. Thanks.

[heathfield]

BTW...If you ever want the degree symbol (�) it's ALT+0176 on the keyboard.