We can use the number line as a model to help us visualize adding and subtracting of signed integers. Just think of addition and subtraction as directions on the number line. There are also several rules and properties that define how to perform these basic operations. To add integers having the same sign, keep the same sign and add the absolute value of each number. To add integers with different signs, keep the sign of the number with the largest absolute value and subtract the smallest absolute value from the largest. Subtract an integer by adding its opposite.

Watch out! The negative of a negative is the opposite positive number. That is, for real numbers, -(-a) = +a

Here's how to add two positive integers:
4 + 7 = ?
If you start at positive four on the number line and move seven units to the right, you end up at positive eleven. Also, these integers have the same sign, so you can just keep the sign and add their absolute values, to get the same answer, positive eleven. Here's how to add two negative integers:

-4 + (-8) = ?
If you start at negative four on the number line and move eight units to the left, you end up at negative twelve. Also, these integers have the same sign, so you can just keep the negative sign and add their absolute values, to get the same answer, negative twelve. Here's how to add a positive integer to a negative integer:

-3 + 6 = ?
If you start at negative three on the real number line and move six units to the right, you end up at positive three. Also, these integers have different signs, so keep the sign from the integer having the greatest absolute value and subtract the smallest absolute value from the largest. Subtract three from six and keep the positive sign, again giving positive three. Here's how to add a negative integer to a positive integer: 5 + (-8) = ?

If you start at positive five on the real number line and move eight units to the left, you end up at negative three. Also, these integers have different...

...THE REAL NUMBER SYSTEM
The real number system evolved over time by expanding the notion of what we mean by the word “number.” At first, “number” meant something you could count, like how many sheep a farmer owns. These are called the natural numbers, or sometimes the counting numbers.
Natural Numbers
or “Counting Numbers”
1, 2, 3, 4, 5, . . .
* The use of three dots at the end of the list is a common mathematical notation to indicate that the list keeps going forever.
At some point, the idea of “zero” came to be considered as a number. If the farmer does not have any sheep, then the number of sheep that the farmer owns is zero. We call the set of natural numbers plus the number zero the whole numbers.
Whole Numbers
Natural Numbers together with “zero”
0, 1, 2, 3, 4, 5, . . .
About the Number ZeroWhat is zero? Is it a number? How can the number of nothing be a number? Is zero nothing, or is it something?Well, before this starts to sound like a Zen koan, let’s look at how we use the numeral “0.” Arab and Indian scholars were the first to use zero to develop the place-value number system that we use today. When we write a number, we use only the ten numerals 0, 1, 2, 3,...

...Polynomial
The graph of a polynomial function of degree 3
In mathematics, polynomials are the simplest class of mathematical expressions (apart from the numbers and expressions representing numbers). A polynomial is an expression constructed from variables (also called indeterminates) and constants (usually numbers, but not always), using only the operations of addition, subtraction, multiplication, and non-negative integer exponents (which are abbreviations for several multiplications by the same value). However, the division by a constant is allowed, because the multiplicative inverse of a non-zero constant is also a constant. For example, x2 − x/4 + 7 is a polynomial, but x2 − 4/x + 7x3/2 is an algebraic expression that is not a polynomial, because its second term involves a division by the variable x (the term 4/x), and also because its third term contains an exponent that is not a non-negative integer (3/2).
A polynomial function is a function which is defined by a polynomial. Sometimes, the term polynomial is reserved for the polynomials that are explicitly written as a sum (or difference) of terms involving only multiplications and exponentiation by non negative integer exponents. In this context, the other polynomials are called polynomial expressions. For example, is a polynomial expression that represents the same thing as the polynomial The term "polynomial", as an adjective, can also be used for quantities that can...

...Pi has always been an interesting concept to me. A number that is infinitely being calculated seems almost unbelievable. This number has perplexed many for years and years, yet it is such an essential part of many peoples lives. It has become such a popular phenomenon that there is even a day named after it, March 14th (3/14) of every year! It is used to find the area or perimeter of circles, and used in our every day lives. Pi is used in things such as engineering and physics, to the ripples created when a drop of water falls into a puddle, Pi is everywhere. While researching this topic I have found that Pi certainly stretches back to a period long ago. The history of Pi was much more extensive than I originally imagined. I also learned that searching for more numbers in Pi was a major concern for mathematicians in which they put much effort into finding these lost numbers. The use for Pi was also significantly larger than I originally anticipated. I was under the impression that it was used for strictly mathematicians which is entirely not true. This is why Pi is so interesting.
The history of Pi dates back to a much later period than I thought. Ancient Egypt and Babylon are one of the first places that Pi was first founded. When discovered it showed that these ancient Pi values were within one percent of it's actual value, which is incredible considering the resources that weren't available yet like we have...

...RATIONAL NUMBERS
In mathematics, a rational number is any number that can be expressed as the quotient or fraction p/q of two integers, with the denominator q not equal to zero. Since q may be equal to 1, every integer is a rational number. The set of all rational numbers is usually denoted by a boldface Q it was thus named in 1895 byPeano after quoziente, Italian for "quotient".
The decimal expansion of a rationalnumber always either terminates after a finite number of digits or begins to repeat the same finite sequence of digits over and over. Moreover, any repeating or terminating decimal represents a rational number. These statements hold true not just for base 10, but also for binary, hexadecimal, or any other integer base.
A real number that is not rational is called irrational. Irrational numbers include √2, π, and e. The decimal expansion of an irrational number continues forever without repeating. Since the set of rational numbers is countable, and the set of real numbers is uncountable, almost all real numbers are irrational.
The rational numbers can be formally defined as the equivalence classes of the quotient set is the set of all ordered pairs(m,n) where m and n are integers, n is not 0 (n ≠ 0), and "~" is the equivalence relation defined...

...In mathematics, a real number is a value that represents a quantity along a continuous line. The real numbers include all the rational numbers, such as the integer −5 and the fraction 4/3, and all the irrational numbers such as √2 (1.41421356... the square root of two, an irrational algebraic number) and π (3.14159265..., a transcendental number). Real numbers can be thought of as points on an infinitely long line called the numberline or real line, where the points corresponding to integers are equally spaced. Any real number can be determined by a possibly infinite decimal representation such as that of 8.632, where each consecutive digit is measured in units one tenth the size of the previous one. The real line can be thought of as a part of the complex plane, and correspondingly, complex numbers include real numbers as a special case.
These descriptions of the real numbers are not sufficiently rigorous by the modern standards of pure mathematics. The discovery of a suitably rigorous definition of the real numbers — indeed, the realization that a better definition was needed — was one of the most important developments of 19th century mathematics. The currently standard axiomatic definition is that real...

...
TUTORIAL: NUMBER SYSTEM
1. Determine whether each statement is true or false
a) Every counting number is an integer
b) Zero is a counting number
c) Negative six is greater than negative three
d) Some of the integers is natural numbers
2. List the number describe and graph them on the numberline
a) The counting number smaller than 6
b) The integer between -3 and 3
3. Given S = {-3, 0,[pic], [pic], e, , 4, 8…}, identify the set of
(a) natural numbers (b) whole numbers (c) integers
(d) rational numbers (e) irrational numbers (f) real numbers
4. Express each of the numbers as a quotient [pic]
(a) 0.7777…… (b) 2.7181818….
5. Write each of the following inequalities in interval notation and show them on the real numberline.
(a) 2 < x < 6 (b) (5 < x < (1
(c) (3 ( x ( 7 (d) (2 < x ( 0
(e) x < 3 (f) x ( (1
(g) x ( (2 (h) (3 ( x < 2
6. Show each of the following intervals on the real numberline.
(a) [(2, 3] (b) ((4, 4)
(c) (((, 5] (d) [(1, ()
(e) ((3, 6] (f) [(2, 3)
(g) ((2, 0) ( (3, 6) (h) [(6, 2) ( [(3, 7)
2 Evaluate
(a) [pic] (b) 27[pic] (c) [pic] (d) [pic]
(e) (0.36)[pic] (f) (2.56)[pic] (g) [pic] (h)...

...Mathematics Chapter 1: Number Systems Chapter Notes
Key Concepts 1. 2. 3. 4. 5. Numbers 1, 2, 3……., which are used for counting are called Natural numbers and are denoted by N. 0 when included with the natural numbers form a new set of numbers called Whole number denoted by W -1,-2,-3……………..- are the negative of natural numbers. The negative of natural numbers, 0 and the natural number together constitutes integers denoted by Z. The numbers which can be represented in the form of p/q where q 0 and p and q are integers are called Rational numbers. Rational numbers are denoted by Q. If p and q are coprime then the rational number is in its simplest form. Irrational numbers are the numbers which are non-terminating and non-repeating. Rational and irrational numbers together constitute Real numbers and it is denoted by R. Equivalent rational numbers (or fractions) have same (equal) values when written in the simplest form. Terminating fractions are the fractions which leaves remainder 0 on division. Recurring fractions are the fractions which never leave a remainder 0 on division. There are infinitely many rational numbers between any two rational numbers. If Prime factors of the denominator are 2...

...he number theory or number systems happens to be the back bone for CAT preparation. Number systems not only form the basis of most calculations and other systems in mathematics, but also it forms a major percentage of the CAT quantitative section. The reason for that is the ability of examiner to formulate tough conceptual questions and puzzles from this section. In number systems there are hundreds of concepts and variations, along with various logics attached to them, which makes this seemingly easy looking topic most complex in preparation for the CAT examination. The students while going through these topics should be careful in capturing the concept correctly, as it’s not the speed but the concept that will solve the question here. The correct understanding of concept is the only way to solve complex questions based on this section.
Real numbers: The numbers that can represent physical quantities in a complete manner. All real numbers can be measured and can be represented on a numberline. They are of two types:
Rational numbers: A number that can be represented in the form p/q where p and q are integers and q is not zero. Example: 2/3, 1/10, 8/3 etc. They can be finite decimal numbers, whole numbers, integers, fractions.
Irrational numbers: A number that...