Drexel dragonThe Math ForumDonate to the Math Forum

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

Dividing and Rounding


Date: 08/23/2001 at 20:41:40
From: Britt
Subject: Dividing and rounding

I have to answer a division problem and then round the quotient to 
the nearest hundredth. The problem is: 

6 divided by 312.8

I solved and got 52.13. Now I have to round it to the nearest 
hundredth. What do I do?

Britt


Date: 08/23/2001 at 22:53:30
From: Doctor Peterson
Subject: Re: Dividing and rounding

Hi, Britt.

First, let's correct your terminology. You didn't divide 6 by 312.8; 
you divided 312.8 by 6. A lot of students say it backward because we 
write the divisor on the left when we do the work.

Your answer really isn't exactly 52.13; if it were, you would be done, 
because there's no rounding to do. Because you had a remainder, you 
should have kept going for another digit; you would get 52.133. In 
fact, the answer is exactly 52.13333..., where the 3's keep going 
forever.

Now that you have an extra digit, you have something to round off. If 
it had been 5 or more, you would have to round up to 52.14; but since 
it is a 3, your answer of 52.13 turns out to be correct.

Here's the key to this kind of question: go one digit beyond the 
number you need to end up with, and then round off that last digit. 
That ensures that whatever remainder you would have had "has its say," 
by forcing you to round in the right direction. Then your answer is 
correct to the nearest hundredth.

- Doctor Peterson, The Math Forum
  http://mathforum.org/dr.math/   
    
Associated Topics:
Elementary Division
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
© 1994-2013 The Math Forum
http://mathforum.org/dr.math/