Math tips, Math formulas

Mathematics
It is the study of numbers, quantities, shapes, and space using mathematical processes, rules, and symbols. There are many branches of mathematics and a large vocabulary associated with this subject.
Here are some math words and terms you will likely come across, but may not know their precise meanings. Any word or term shown in bold is defined in the following alphabetical list of math words and terms.
Algorithm
A step-by-step mathematical procedure used to find an answer.
Coefficient
A number that multiplies a variable. For example, 9 is the coefficient in 9x.
Denominator
The bottom number in a fraction. The denominator represents the number of parts into which the whole is divided. For example, 6 is the denominator in the fraction is an improper fraction.
Inverse Operations
Opposite or reverse operations. Addition and subtraction are inverse operations, as are multiplication and division.
Negative Number
A number that is less than zero. A minus sign is used to show that a number is negative. For example, -12 is a negative number.
Numerator
The top number in a fraction. The numerator represents the number of parts of the whole.
Ordinal Number
A number that shows place or position, as in 2nd place.
Positive Number
A number that is greater than zero. While a minus sign is used to signify a negative number, the absence of a minus sign signifies a positive number.
Prime Number
A number that can be divided evenly only by itself and 1. For example, 7 is a prime number.
Square Number
A number that results from multiplying another number by itself. For example, 49 is the square of 7 (7 x 7 = 49).
Square Root of a Number
A number that is multiplied by itself to produce a square number. For example, 7 is the square root of 49. It is designated by the symbol √.
Variable
A quantity that can change or vary, taking on different values. It is typically represented by a letter of the alphabet. For example x is the variable in 9x (x can be any number that is being multiplied by 9).

Roman Numerals
FPRIVATE "TYPE=PICT;ALT=Roman Numerals, Clock"
You can guess from their name that Roman Numerals originated in ancient Rome. They were created as a simple means of counting in which certain letters are given values as numerals (a numeral is a written symbol referring to a number). The original system of Roman Numerals was modified during the Middle Ages and is the system we still use today.
Seven letters form the basis of Roman Numerals. Each letter stands for a number as shown here.
ROMAN NUMERALS
I = 1 V = 5
X = 10 L = 50
C = 100 D = 500
M = 1,000
Reading and Writing Roman Numerals
Numbers are represented by combining the letters shown above. There are several rules to follow.
If one or more letters are placed after another letter of greater value, add that amount.
VI = 6 (5 + 1 = 6)
XXVII = 27 (10 + 10 + 5 + 1 + 1 = 27)
MDC = 1,600 (1,000 + 500 + 100 = 1,600)
A letter cannot be repeated more than three times.
30 = XXX (10 + 10 + 10 = 30)
40 = XL (50 - 10 = 40) You cannot write 40 as XXXX.
If a letter is placed before another letter of greater value, subtract that amount.
IX = 9 (10 - 1 = 9)
XL = 40 (50 - 10 = 40)
CML = 950 (900 + 50 = 950)
You can only subtract powers of 10 (I, X, C).
95 = XCV (100 - 10 + 5 = 95)
You cannot write 95 as VC because V is not a power of 10.
You cannot subtract more than one number from another number.
18 = XVIII (10 + 5 + 1 + 1 + 1 = 18)
You cannot write 18 as IIXX.
By the way, there is no zero in the system of Roman Numerals.

DMAS Rule
D: Division
M: Multiplication
A: Addition
S: Subtration
This rule basically design for those students who have problems for addition, multiplication, subtraction and division. They are confused that what they can solve.
First of all, You can divide then Multiply then add and then subtract the values.