VOCABULARY Nº1 : WORKING WITH NUMBERS

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Numeral System:
A numeral system (or system of numeration) is a framework where a set of numbers are represented by numerals in a consistent manner.

Natural number:
The set of natural numbers is 1,2,3....

Integer number :
The Integers consist of the positive natural numbers (1, 2, 3, …), their negatives (-1, -2, -3, ...) and the number zero

Rational number:
A rational number (commonly called a fraction) is a ratio or quotient of two integers, usually written as the vulgar fraction a/b, where b is not zero.
A rational number is said to have numerator and denominator

Fraction:
A fraction is a way of expressing a quantity based on an amount that is divides into a number of equal-sized parts.

Equivalent fractions:
Multiplying the numerator and denominator of a fraction by the same (non-zero) number results in a new fraction that is said to be equivalent to the original fraction. The word equivalent means that the two fractions have the same value.

Irrational number:
An irrational number is any real number that is not a rational number, i.e., that cannot be expressed by a quotient of two integers, i.e. it cannot be written as a fraction in which the numerator and denominator are integers.

Square root:
A square root of x is a number r such that r*r = x.

Nth root:
In mathematics, an nth root of a number a is a number b, such that b^n=a
The quantity under the root is called the radicand, and the quantity n is called the index.

Golden ratio:
The golden ratio expresses the relationship that the sum of two quantities is to the larger quantity as the larger is to the smaller. The golden ratio is the following algebraic irrational number with its numerical approximation:

Real number:
The set of all rational and irrational numbers

Prime number:
In mathematics, a prime number (or a prime) is a natural number that has exactly two (distinct) natural number divisors, which are 1 and the prime number itself.

Least common multiple:
The least common multiple or lowest common multiple (lcm) or smallest common multiple of two integers a and b is the smallest positive integer that is a multiple of both a and b.

Greatest common divisors:
The greatest common divisor (gcd), sometimes known as the greatest common factor (gcf) or highest common factor (hcf), of two non-zero integers, is the largest positive integer that divides both numbers without remainder.

Complex number:
The complex numbers are the field of numbers of the form a+bi, where a is a real number called real part, b is a real number called imaginary part and i is the imaginary unit equal to the square root of -1.

Absolute value:
The absolute value (or modulus1) of a real number is its numerical value without regard to its sign.

Interval:
An interval is a set that contains every real number between two indicated numbers and possibly the two numbers themselves.

Error :
The difference between a quantity and its estimated or measured quantity.

Absolute error:
Given some value a and an approximation b of a, the absolute error is

Relative error:
Given some value a and an approximation b of a, the absolute error is