Ordering DecimalsDate: 10/17/98 at 22:03:30 From: C. Dunham Subject: Comparing and ordering decimals My daugther is in 5th grade and is having a problem with comparing decimals. For example, is .467 less than, greater than, or equal to .465? What is the easiest way to teach her and for her to remember it? Date: 10/19/98 at 13:05:35 From: Doctor Peterson Subject: Re: Comparing and ordering decimals I think I would start with what she already knows about comparing whole numbers. To compare 467 and 465, she would line them up with the ones digits together: 467 465 and look for the first place where they are different, starting from the left. The 4's are the same, the 6's are the same, so the difference is between the 7 and the 5, making 467 bigger than 465. This is because the digits on the left are most "valuable." If you have more hundreds, it doesn't matter whether you have fewer tens. To compare decimals you do exactly the same thing, as long as you remember to line up the ones digits (or the decimal points), not the rightmost digits, which might have different values. Here's an example of that: 4.67 4.654 I've lined up the decimal points; the 4's and the 6's match, so the first difference is in the hundredths place, where 7 > 5, so 4.67 > 4.654. So the keys are to make sure you are comparing hundreds with hundreds, and so on, and to start with the most valuable places. I think this method should give her both a comforting routine to follow, and an understanding of what it means, both of which are important. Let me know whether that helps! - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/ |
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