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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 

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

  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
Associated Topics:
Elementary Fractions
Middle School Fractions

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