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Q&A #2179 |
From: Diane White
To: Teacher2Teacher Public Discussion
Date: 2002091817:46:52
Subject: Teaching algebraic expressions
The one thing that I found is that the wording in an expression is everything. I have taught pre-algebra for many years and can offer you this advice: 1. Explain the simple number statements first: 3+4; 5x6; 28/4, etc. 2. Now substitue a variable for a value. Example rather than 3+4, we have x+4. 3. Turn the standard form numbers into words for the simple math facts: three plus four; five times six, etc. 4. Now substitute the variable for the number in words: x plus 4; five times x; 28 divided by x or x divided by 7 5. Give the students a list of the various words meaning addition: plus, sum of, increased by, more, more than - to cite just a few. Follow this up with subtraction, multiplication and division terms. 6. Have them become extremely familiar with all the key words. 7. Now, teach them the difference between a math statement and an algebraic expression. It is a simple matter of substituting a variable for a number. 8. Be very careful to note the following: When you use more than and less than you must explain to your students that the values here are transposed. Example: 5 more than a number is not 5+x but x+5. Example: 10 less than a number is not 10 - x but x - 10. This is the only case in all of pre-algebra that the students the value of proper placement of value and variable. 9. When all is said and done, and your students cannot determine the difference between a constant value and a variable - do what I started many years ago. I simply explain to my students that a constant value - one which never changes - is my height. It stays at 5'3". However, my weight is a variable - it changes all the time hourly as I get older! Hope that this was informative - if not it was nice speaking to you Teacher To Teacher. Diane White
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