Dividing Decimals by Whole NumbersDate: 10/19/2002 at 16:14:39 From: Troubled Subject: Dividing Decimals by whole numbers Dividing decimals has been the hardest concept for me to learn. - Troubled Date: 10/19/2002 at 16:28:28 From: Doctor Ian Subject: Re: Dividing Decimals by whole numbers Hi, Can you divide whole numbers by other whole numbers? For example, can you do this? 219 _____ 15 ) 3295 30 -- 29 15 -- 145 135 --- 10 If so, then you can do the same thing with a decimal point: 2.1 9 ________ 15 ) 3 2.9 5 3 0 --- 2 9 1 5 --- 1 4 5 1 3 5 ----- 1 0 You just leave the decimal point where it is. Now, what about that remainder? Well, note that adding zeros to a decimal number after the decimal point doesn't change the value of the number, e.g., 32.95 = 32.950 = 32.9500 = ... = 32.950000000 = ... So when you run out of other digits to bring down, you start bringing down zeros instead: 2.1 9 6 6 6 ______________ 15 ) 3 2.9 5 0 0 0 3 0 --- 2 9 1 5 --- 1 4 5 1 3 5 ----- 1 0 0 9 0 ----- 1 0 0 9 0 ----- 1 0 Now, when you do this, one of two things will eventually happen. The first is that you'll end up with no remainder, in which case, you're done. The second thing that can happen is illustrated above: you fall into a pattern where the same thing keeps happening over and over. In this case, you're also done, and what you have is a repeating decimal. You can indicate the repeating part by putting a bar over the pattern that repeats. So in this case, we would get 2.1 9 6 6 6 ______________ _ 15 ) 3 2.9 5 0 0 0 = 2.196 So, to recap, dividing a decimal by a whole number works just like dividing a whole number by a whole number, except there is a decimal point (which you just leave where it is), and you keep adding zeros at the end until you get no remainder, or until you get into a repeating pattern. I hope this helps. Write back if you'd like to talk more about this, or anything else. - Doctor Ian, The Math Forum http://mathforum.org/dr.math/ |
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