Arithmetic Course/Types of Number/Fraction Number

Fraction Number
Number has the general form of a Numerator over a Denominator
 * $$\frac{A}{B}$$

Equal Fraction

 * $$\frac{A}{B} = \frac{C}{D}$$ when A = C and B = D

Common Denominator

 * $$\frac{A}{B} (\frac{D}{D}) = \frac{C}{D} (\frac{B}{B})$$


 * $$\frac{A D}{B D} = \frac{B C}{B D}$$

Addition

 * $$\frac{A}{B} + \frac{C}{D} = \frac{AD + BC}{BD}$$

Subtraction

 * $$\frac{A}{B} - \frac{C}{D} = \frac{AD - BC}{BD}$$

Multiplication

 * $$\frac{A}{B} \times \frac{C}{D} = \frac{AC}{BD}$$

Division

 * $$\frac{A}{B} / \frac{C}{D} = \frac{AD}{BC}$$

Rational Number
Fraction can be expressed as Rational Number
 * $$\frac{1}{4} = 0.25$$

Irrational Number
Fraction can be expressed as Irrational Number
 * $$\frac{1}{3} = 0.333333....$$

Irratioal Constants
 * $$\pi = 3.1415...$$
 * $$e = 2.72...$$