Writing Expressions with Variables
Date: 09/13/98 at 21:56:54 From: Uriah Rice Subject: How to do the problem and the answer to the problem Write an expression that represents a $500 donation plus $5 for every event. Let n represent the number of events. I do not understand what the problem wants me to write.
Date: 09/14/98 at 08:15:08 From: Doctor Rick Subject: Re: How to do the problem and the answer to the problem Hi, Uriah. I presume you are being guided through the solution of a word problem. Either you were given the word problem, and you are going through it one step at a time, or you are just practicing what you would do if you had the whole problem. An expression is a collection of numbers and variables connected by arithmetic operations (add, multiply, etc.) so that if you worked out all the arithmetic, you would get a number. In this case, the number you would get would be the total payment. Let's say you knew there were 4 events. Could you then work out how much to pay? It would be: 500 + 5 * 4 in dollars. This is an expression. You can work it out and get the answer of 520. (In case this is your first time working with math on a computer, we use "*" to represent multiplication, because "x" might be a variable.) In fact, you don't know how many events there are. But whatever that number turned out to be, you could put it in place of the "4" in the expression and work it out in just the same way. So what we do is use a letter as a name to stand for whatever number we will end up putting there. This is a variable. It is sort of a place holder for a number. You were asked to use the letter "n" to represent the number of events. That means "n" will be our variable, and we can put it in place of the 4, like this: 500 + 5 * n When multiplying by a variable, we don't need to write the "*". You can just write: 500 + 5n I hope this helps you work out other problems in writing expressions. - Doctor Rick, The Math Forum Check out our web site! http://mathforum.org/dr.math/
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