The Math Forum

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

Adding Mixed Numbers

Date: 12/10/95 at 11:57:56
From: Anonymous
Subject: Fractions

   3 1/4 + 5 3/12

I've been trying this over and over again and I still don't get it!  
Please help.

Date: 12/11/95 at 11:45:59
From: Doctor Ken
Subject: Re: Fractions


There are a couple of different ways you could approach this problem.  
You could either convert the mixed numerals to improper fractions and 
then add, or you could add the parts separately.  Here's what I mean 
when I say you could add the parts separately.

Ask yourself "what does 3 1/4 mean?"  It means 3 + 1/4. Similarly, 
5 3/12 means 5 + 3/12. So 3 1/4 + 5 3/12 just means 3 + 1/4 + 5 + 3/12.  
So that's four numbers that we can add together.  I think it's easiest 
to add the 3 and the 5 together, and then add the 1/4 and the 3/12 

Now 3 + 5 = 8, and what is 1/4 + 3/12?  Hint: you're going to have to 
get a common denominator. Do you know what a denominator is? It's the 
part on the bottom of the fraction. So once you do that, you'll have 
your answer: it will be 8 and whatever your answer is to the fraction 
addition part.

Good luck!

- Doctor Ken,  The Geometry Forum

Associated Topics:
Elementary Fractions

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.