Associated Topics || Dr. Math Home || Search Dr. Math

### Distributing Division

```Date: 11/23/2003 at 12:50:01
From: Kathryn
Subject: Mathematics Explained For Primary Teachers

Hi,

Hope I'm not wasting your time but I hope that you can help.

On page 91 of the book _Mathematics Explained For Primary Teachers_
(by Derek Haycock), I find this statement:

The method is based on the distributive law for division

Shouldn't this read '....distributive law for multiplication

Kathryn
```

```
Date: 11/23/2003 at 22:49:57
From: Doctor Ian
Subject: Re: Mathematics Explained For Primary Teachers

Hi Kathryn,

Well, division _does_ distribute over addition, e.g.,

(1 + 2)/5 = 1/5 + 2/5

which is why we can add fractions with common denominators by simply
adding their numerators.  However, it's only left-distributive,

(1 + 2)/5 = 1/5 + 2/5            Yes

5/(1 + 2) = 5/1 + 5/2            No

whereas multiplication is both left- and right-distributive:

5(1 + 2) = 5(1) + 5(2)           Yes

(1 + 2)5 = 1(5) + 2(5)           Yes

Does this help?

- Doctor Ian, The Math Forum
http://mathforum.org/dr.math/
```
Associated Topics:
Elementary Division

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