Date: Fri, 11 Nov 1994 11:03:41 -0700 (MST) From: John Murgel Subject: pre-algebra I am a teacher and would like to run this by you guys. Here is the problem: how would you go about helping a typical 7th grade student? -3n + 65 = -40 - 7n My math count students will be working problems such as this in their state contest.
Date: Fri, 11 Nov 1994 16:55:59 -0500 (EST) From: "Michael W. S. Morton" Subject: Re: pre-algebra Hey there! I'm one of the Math Doctors here. I'll show you what I'd do to try to help out a 7th grader, and maybe some of the other math doctors have other ideas. > -3n + 65 = -40 - 7n I may start with something like: n + 5 = 12 then ask what numbers would work there? (7). Ask how the student came up with that answer. Then explain it in this way: n + 5 = 12 subtract 5 from both sides of the equation: n + 5 - 5 = 12 -5 n = 7 If subtracting a number from both sides of the equation is not clear to a student, try saying: 1 = 1 does 1 - 5 = 1 - 5 ?? Since n represents a number ( a real, physical number) we can add or subtract a real number to both sides and not change anything. So, moving on.... Then say: 2n + 5 = 13 2n + 5 - 5 = 13 - 5 2n = 8 n = 4 This should be relatively clear. You can go from there... As I'm typing this, I'm thinking this is not quite what you wanted to know (or wanted to hear) If it is not, PLEASE write us back, and we'll try to help you out some more. Sorry if this is over-simplified or not what you wanted; just write back and let us know! -MORTON, Doctor of sorts
Search the Dr. Math Library:
Ask Dr. MathTM
© 1994-2015 The Math Forum