BracketsDate: 01/29/2001 at 23:40:29 From: James Subject: Brackets I had a test and on it there was a question about brackets. I would like you to explain to me how these brackets [] work. Thanks! (In advance.) Date: 01/30/2001 at 08:54:53 From: Doctor Peterson Subject: Re: Brackets Hi, James. I'm going to assume you are referring to the ordinary use of brackets, where they mean the same thing as parentheses, "()". There are special ways they are used in more advanced fields, but you probably are not doing that. You can read about this in our FAQ on "Order of Operations": http://mathforum.org/dr.math/faq/faq.order.operations.html Brackets are a way to modify the order in which you would ordinarily evaluate an expression, when you want to say something that can't be written the usual way. For example, suppose I want you to add the numbers 1 and 2, then multiply the result by 3. If I wrote 1 + 2 * 3 (using "*" as the multiplication sign), it would mean that you would multiply 2 and 3 first, then add 1, since the rules say to multiply first. But if I "package" the expression "1 + 2" together in such a way that you are required to evaluate it first and then treat it as a single number, then you will do what I want. That's what brackets are for. When I write [1 + 2] * 3 it means to first turn everything inside the [...] into a single number, then multiply by 3. The answer will be 9. That's what it's all about, in general. If you have some problems you can't figure out using this basic explanation, send them to us so we can explain any details I've missed. It might help if you could show us how you tried to solve the problems, so we can see where you need help. - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/ |
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