The Math Forum

Ask Dr. Math - Questions and Answers from our Archives
Associated Topics || Dr. Math Home || Search Dr. Math

Use and Meaning of 'And' in Naming Decimals

Date: 12/01/2004 at 20:11:12
From: Emily
Subject: May you please tell me what the word "and" means in math?

Dear Dr. Math,

Can you please tell me what the word "and" means in the word form of a
decimal number?  I don't normally see it when it is not used for math!

Date: 12/01/2004 at 23:21:59
From: Doctor Peterson
Subject: Re: May you please tell me what the word "and" means in math?

Hi, Emily.

You're probably thinking of the fact that, at least when we read a
number the way teachers commonly insist, "and" is used only between
the whole number and the fractional part.  For example, we would say
"one hundred fifty-two" for "152", but "one AND fifty-two hundredths"
for "1.52".  Of course, in real life people don't always follow that
rule; but it does make sense if you want to be careful in your
speaking.  But the "and" there really doesn't have any different
meaning there than it usually does, to connect two things together,
meaning more or less the same as "plus".  What's more important is
that by only using it at the decimal point, when it is NOT used you
know there is NOT a decimal point there!

The value of using "and" carefully shows up mostly in fractions.  Note
the distinction here:

  one hundred and three hundredths = 100 3/100 = 100.03
  -----------     ----------------

  one hundred three hundredths = 103/100 = 1.03


  one hundred three-hundredths = 100/300 = 1/3 !

See this page:

  Saying Numbers Out Loud 

This page deals with the related issue of hyphens:

  Place Value and Similar Numbers 

If you have any further questions, feel free to write back.

- Doctor Peterson, The Math Forum 
Associated Topics:
Elementary Definitions
Elementary Number Sense/About Numbers
Elementary Place Value

Search the Dr. Math Library:

Find items containing (put spaces between keywords):
Click only once for faster results:

[ Choose "whole words" when searching for a word like age.]

all keywords, in any order at least one, that exact phrase
parts of words whole words

Submit your own question to Dr. Math

[Privacy Policy] [Terms of Use]

Math Forum Home || Math Library || Quick Reference || Math Forum Search

Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.