Dividing Two DecimalsDate: 8/30/95 at 16:23:1 From: Anonymous Subject: Decimal Division Dear Dr. Math, I do not understand division when you are dividing a decimal into another decimal number. Please help! From a 6th grade student in Mt. Vernon, New York Date: 9/3/95 at 18:3:5 From: Doctor Heather Subject: Re: Decimal Division Hi. I guess the best way I can help you is to give you a few examples, and try to explain exactly what I'm doing along the way. Let's start with dividing a one-place decimal into another one-place decimal: .2/.5 ___ .5 ).2 The first thing we need to do is take care of the decimal in the divisor position (.5). This number must always be "changed" to a non-decimal. What I mean by "changed" is that we basically multiply both the divisor and the dividend by 10. [Check this out for yourself and see if you think this is okay. For example, is 100/20 the same as 1000/200?] The way I think of it is that you're moving the decimal of the dividend (.2) as many places to the right as there are decimal places in the divisor. In this case, the divisor only has one decimal place. So, we have ____ 5 )2.0 We need to show where the decimal point is in the dividend. The next thing we need to do is to fix the decimal point of the answer. Just move another decimal point straight up from the position in the dividend. __.__ 5 )2.0 So, now you do normal division. Does 5 go into 2? No, so you can either leave it blank, or put a zero there to remind yourself there's nothing there (and it will ensure that you keep your decimal point in the right place). Does 5 go into 20? Yes, so we put a 4 above the zero. Our final answer is .4 Now let's go through a more complicated problem. _____ .14 ).448 The first thing we do is take care of the decimal point of the divisor (multiply by 100). We move the decimal of the dividend over two places. Now we have ______ 14 )44.8 Position the decimal point, ___.__ 14 )44.8 and divide as usual. Try it out and see if you get 3.2 If you have trouble, write back and try to explain some more, like a specific problem you're having trouble with. Good luck! - Doctor Heather, The Geometry Forum |
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