+0

# fraction Dividing

0
183
1

why do you multiply fractions instead of dividing? cause my teacher always said to invert and multiply and i was confused why.

Guest Jun 13, 2017

#1
+6347
+2

It is easier to multiply fractions.

For example:

$$\frac34\div\frac57=\frac34\,*\,\frac75$$

Then, just multiply straight across.

$$=\frac{3*7}{4*5}=\frac{21}{20}$$

It  is  true that

$$\frac34\div\frac57=\frac{3\div5}{4\div7}=\frac{21}{20}$$

But how are you going to evaluate   3 / 5    and   4 / 7    without using a calculator or long division?

And...to see why inverting and multiplying is the same as dividing, take a simple example:

$$10\div2=10\,*\,\frac12=\frac{10}{1}\,*\,\frac12=\frac{10}{2}$$

hectictar  Jun 14, 2017
Sort:

#1
+6347
+2

It is easier to multiply fractions.

For example:

$$\frac34\div\frac57=\frac34\,*\,\frac75$$

Then, just multiply straight across.

$$=\frac{3*7}{4*5}=\frac{21}{20}$$

It  is  true that

$$\frac34\div\frac57=\frac{3\div5}{4\div7}=\frac{21}{20}$$

But how are you going to evaluate   3 / 5    and   4 / 7    without using a calculator or long division?

And...to see why inverting and multiplying is the same as dividing, take a simple example:

$$10\div2=10\,*\,\frac12=\frac{10}{1}\,*\,\frac12=\frac{10}{2}$$

hectictar  Jun 14, 2017

### 24 Online Users

We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details