Date: 10/31/2001 at 11:08:19
From: Mike
Subject: Give the power of ten (decimals)
Dear Dr. Math,
Can you help me with this problem? The directions are:
Give the power of ten that the decimal must be multiplied by to
eliminate the decimal point.
3.825 6.91 19.207
My mom and I can not seem to figure this out.
Thanks, Mike
Date: 10/31/2001 at 12:10:14
From: Doctor Peterson
Subject: Re: Give the power of ten (decimals)
Hi, Mike.
A power of ten is a number formed by multiplying a bunch of 10's
together, like 1000 = 10*10*10. (I use "*" as the multiplication
sign.)
When you multiply a number by ten, you move the decimal point one
place to the right; for instance
12.0 * 10 = 120.
1.2 * 10 = 12.
So if you have to move the decimal point three places to the right to
make a whole number, then you are multiplying by ten three times, and
this is the same as multiplying by 1000:
1.234 * 1000 = 1.234 * 10*10*10
= 12.34 * 10*10
= 123.4 * 10
= 1234.
In other words, just count the decimal places, write that many zeros
after a 1, and you have the number by which you have to multiply to
eliminate the decimal point:
1.234 1000
\_/ \_/
3 3
The number 1000 is written as the third power of 10, or
3
1000 = 10*10*10 = 10
\______/
3
Does that help?
- Doctor Peterson, The Math Forum
http://mathforum.org/dr.math/