Finding Decimals on a Number Line

Date: 01/16/2002 at 18:34:12
From: Hubert
Subject: Finding decimals on a number line

How can I find a number like 0.725 on a number line?

Date: 01/16/2002 at 22:38:27
From: Doctor Peterson
Subject: Re: Finding decimals on a number line

Hi, Hubert.

One way is to do it one digit at a time. 

First find 0; your number is between 0 and 1. Now divide that interval 
into 10 equal parts; 0.7 is 7 tenths past 0:

                                |
    +---+---+---+---+---+---+---+---+---+---+
    0  0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9  1.0


Now your number is between 0.7 and 0.8. Divide that interval into ten 
equal parts, and 0.72 is 2 hundredths past 0.7:

            |
    +---+---+---+---+---+---+---+---+---+---+
   .7  .71 .72 .73 .74 .75 .76 .77 .78 .79 .80


Do you see the last step?

You can also recognise that .25 is 1/4, so 0.725 is 1/4 of the way 
from 0.7 to 0.8; but if you don't see that, don't worry about it.

- Doctor Peterson, The Math Forum
  http://mathforum.org/dr.math/