Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

This is an AMP page - Open full page! for all features.

• the most efficient way to navigate the Engineering ToolBox!

# Fractions

## Law of fractions

Fractions consist of two basic parts:

• denominator - or bottom number
• numerator - or the top number

Fraction:

a / b                      (1)

where

a = numerator

b = denominator

• proper fraction - the nominator smaller than the denominator
• improper fraction - the nominator larger than the denominator
• reducible fraction - is a fraction that can be reduced to lower terms
• least common denominator - the smallest denominator value divisible
• mixed number - a combination of a whle number and a fraction

### Laws of Fractions

(a / b) + (c / d) = (a d + b c) / (b d)                    (2)

(a / b) (c / d) = (a c) / (b d)                             (3)

(a / b) / (c / d) = (a / b) (d / c)                             (4)

(- a / b) = - (a / b) = a / (- b)                            (5)

[(a / b) + (c / d)] / [(e / f) + ( g / h)]

= ([(a / b) + (c / d)] / [(e / f) + (g / h)]) ([b d f h] / [b d f h])

= [((a d) + (b c)) f h] / [((e h) + (f g)) b d]                   (6)

(1 / 4) + (3 / 16) + (7 / 8)

= (4 / 4) (1 / 4) + (3 / 16) + (2 / 2) (7 / 8)

= (4 / 16) + (3 / 16) + (14 / 16)

= (4 + 3 + 14) / 16

= 21 / 16

### Multiplying Fractions - Example

(3 / 4) (9 / 16)

= ((3) (9)) / ((4) (16))

= 27 / 64

### Dividing Fractions - Example

(3 / 4) / (9 / 16)

= ((3) (16)) / ((4) (9))

= 48 / 36

## Related Topics

• Mathematics - Mathematical rules and laws - numbers, areas, volumes, exponents, trigonometric functions and more.

## Search Engineering ToolBox

• the most efficient way to navigate the Engineering ToolBox!

## SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

## Privacy

We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Temperature

oC
oF

Length

m
km
in
ft
yards
miles
naut miles

Area

m2
km2
in2
ft2
miles2
acres

Volume

m3
liters
in3
ft3
us gal

Weight

kgf
N
lbf

Velocity

m/s
km/h
ft/min
ft/s
mph
knots

Pressure

Pa (N/m2)
bar
mm H2O
kg/cm2
psi
inches H2O

Flow

m3/s
m3/h
US gpm
cfm

3 30