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Do We Need a Zero before the Decimal?

Date: 01/26/2005 at 00:37:05
From: Robin
Subject: Using the decimal point and dollar sign

Are there any set rules about using the decimal point and dollar sign 
even if the money amount is less than $1?  Do I need to use a zero to 
hold the dollar place if the amount is less than a dollar?  I see
money amounts written in both ways--$.45 or $0.45.  Are both correct?  
What is the benefit of using one form over the other if both are 
correct?

I'm thinking that the zero before the decimal point is not needed, but 
I am not sure and would like to know the rule if there is one or the 
resoning behind the customary practice.



Date: 01/26/2005 at 08:28:33
From: Doctor Rick
Subject: Re: Using the decimal point and dollar sign

Hi, Robin.

The question is the same with or without the dollar sign: do we write 
0.4523 or .4523?

The zero is not needed as a place holder; place holders are only 
needed between the decimal point and a significant digit, as in 0.045 
or 430.1.  (Without the place-holder zero, these would be 0.45 and 
43.1, which are very different numbers.)

My personal rule is to include the zero before the decimal point  
whenever I write a decimal less than 1.  My reason for this is very 
practical: the decimal point can get lost easily, and having the zero 
there gives the reader an extra clue to look for the decimal point.  I 
have run into trouble trying to read measurements in plans that were 
faxed to me, when the sender did not put in the zero: for instance, 
2' .5" looked like 2' 5" so I made something 4.5 inches too long.

You could do a web search for standard practices in industries such as 
banking, to see if anyone has formalized this rule.  I do not worry 
about it, because my rule is practical and I can't imagine anyone 
objecting to it.  Here is one style guide I found with a quick search, 
and it agrees with me:

  UUHSC Style Guide
    http://uuhsc.utah.edu/wrc/community/guide/numbers.htm 

  If expressing a value less than one, place a zero before the
  decimal point to help the reader notice the decimal point:
  0.5 percent, not .5 percent. However, in text write 50 cents
  instead of $0.50.

- Doctor Rick, The Math Forum
  http://mathforum.org/dr.math/ 
Associated Topics:
Elementary Fractions
Middle School Fractions

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