## You are here

Homekeep-flip-change

## Primary tabs

# keep-flip-change

Let $a,b,c,d\in\mathbb{Z}-\{0\}$. A mnemonic device for calculating

$\frac{a}{b}\div\frac{c}{d}$ |

is KFC. This stands for ”keep-flip-change”. This means that you keep the first fraction as it is, flip the second fraction, and change the problem to a multiplication problem. Thus, the expression above becomes

$\frac{a}{b}\cdot\frac{d}{c}.$ |

This yields that

$\frac{a}{b}\div\frac{c}{d}=\frac{a}{b}\cdot\frac{d}{c}=\frac{ad}{bc}.$ |

Synonym:

KFC, K.F.C.

Type of Math Object:

Definition

Major Section:

Reference

## Mathematics Subject Classification

97D40*no label found*

- Forums
- Planetary Bugs
- HS/Secondary
- University/Tertiary
- Graduate/Advanced
- Industry/Practice
- Research Topics
- LaTeX help
- Math Comptetitions
- Math History
- Math Humor
- PlanetMath Comments
- PlanetMath System Updates and News
- PlanetMath help
- PlanetMath.ORG
- Strategic Communications Development
- The Math Pub
- Testing messages (ignore)

- Other useful stuff