Choosing an Unknown
Date: 08/06/97 at 20:06:50 From: Rachel Subject: I have a word problem question. What is the easiest way to do a hard word problem?
Date: 08/12/97 at 17:28:50 From: Doctor Mike Subject: Re: I have a word problem question. Dear Rachel, For most people, choosing the unknown is the hardest part. Like "Let X be the unknown number of gallons" "Let D be the distance traveled" "Let A be the angle the see-saw makes with the ground" depending on what the problem is about. You really need to think carefully about this step. It's important to get a good start. Then you usually take information given to you and put it into an equation form like X*pi = 35 D+55 = 100 3*A = 90 You may be given the facts to make 2 equations. From this point on, you work with the numbers and the equations, and try to find the answer. This step is the "pure algebra" step. The most important tool you have to work with is the principle that you can do EXACTLY THE SAME THING to both sides of an equation, and you will wind up with another true thing. Here are some examples: Start out with D+55 = 100. Subtract 55 from both sides and you get D+55-55 = 100-55, which simplifies to D = 45. Start out with 3*A = 90. Divide both sides by 3 and you get (3*A)/3 = 90/3, which simplifies to A = 30. This is about all I can say in general about word problems, but if you send one in to Dr. Math we can show you how to work it out. I find I learn pretty well by looking at some examples, and maybe you will too. -Doctor Mike, The Math Forum Check out our web site! http://mathforum.org/dr.math/
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