ALG
Algebra

AS
Arithmetic Sequence

AP
Arithmetic Progression

GCD
Greatest Common Divisor

LCM
Least Common Multiple

HCF
Highest Common Factor

GCF
Greatest Common Factor

LHS
Left-Hand Side

RHS
Right-Hand Side

PDF
Probability Density Function

CDF
Cumulative Distribution Function

SD
Standard Deviation

Var
Variance

CI
Confidence Interval

PMF
Probability Mass Function

IM
Imaginary Part

Re
Real Part

Q.E.D.
Quod Erat Demonstrandum (that which was to be demonstrated)

df
Degrees of Freedom

RV
Random Variable

LTI
Linear Time-Invariant

ODE
Ordinary Differential Equation

PDE
Partial Differential Equation

LCD
Least Common Denominator

RMS
Root Mean Square

FOIL
First, Outside, Inside, Last (for binomial multiplication)

Pi (?)
Mathematical constant representing 3.14159...

Phi (?)
Golden Ratio

SOP
Sum of Products

COP
Chain of Products