Numbers Flashcards
Real Numbers (R)
Any number that can be identified on the number line. Includes negative numbers, positive numbers, square roots, pi, and almost all other numbers. Non-real numbers cannot be identified on a number line such as the square roots of negative numbers and 0/0.
Properties of Real Numbers
- Commutative Property
- Associative Property
- Distributive Property
- Identity Property
- Inverse Property
Note: The properties of real numbers deal only with addition and multiplication. The properties do not apply to subtraction and division
Commutative Property
A binary operation (equation consisting of two numbers) of addition or multiplication can be rearranged in order and the value will not change.
Addition: 2+3 = 3+2
Multiplication: 2x3 = 3x2
Associative Property
The numbers in equations made up of only addition OR only multiplication can be grouped in any order and the value will not change.
Addition: 2+(3+4) = (2+3)+4
Multiplication: 2x(3x4) = (2x3)x4
Distributive Property
When multiplying a number by a group of numbers being added together in parentheses, the number can be multiplied individually to each of the numbers in parentheses, and the resulting products are added together. The same is true when multiplying a number by a group of numbers being subtracted together in parentheses.
2x(3+4) = (2x3)+(2x4) 2x(3-4) = (2x3)-(2x4)
Identity Property
Adding zero or multiplying one by a number does not change the original value.
Addition: 5+0=5
Multiplication: 5x1=5
Inverse Property
Adding a number by its additive inverse equals zero. Multiplying a number by its multiplicative inverse equals 1.
Addition: 5+(-5) = 0
Multiplication: 5x(1/5)=1
Note: the one exception is zero. Zero is a real number, but there is no additive inverse or multiplicative inverse for the number zero.
Components of Real Numbers
WINQS
- Whole Numbers (W)
- Integers (I)
- Natural Numbers (N)
- Rational Numbers (Q)
- Irrational Numbers (S)
Integers (I)
A number with no fractional part or decimal.
…., -3, -2, -1, 0, 1, 2, 3, ….
Whole Numbers (W)
Non-negative integers that are greater than or equal to zero.
0, 1, 2, 3, 4, …..
Natural Numbers (N)
Non-negative integers greater than or equal to 1 (AKA counting numbers).
1, 2, 3, 4, ….
Rational Numbers (Q)
All fractions consisting of two integers in which the bottom integer is not equal to zero.
Examples: 1/2, 3/4, -2, -2/5, 3
Note: This includes all numbers with repeating decimals such as .22222…. (show notation for repeating decimals), because all such numbers can be re-written as a fraction. .2222… re-written as a fraction is 2/9.
Irrational Numbers (S)
All numbers that are not rational are irrational. This includes numbers with fractional parts in which the decimals do not terminate and do not repeat.
Examples: pi, square root of 2
Proper and Improper Functions
Proper fractions - Fractions in which the numerator is less than the denominator and the value is between -1 and 1. Examples: 1/2, 3/4, 150/160
Improper fractions - Fractions in which the numerator is greater than the denominator (all other fractions besides proper fractions). Examples: 8/5, 3/1, 60/20.
Note: Improper fractions can be re-written as mixed numbers, i.e. 8/5 can be re-written as 1 3/5
Odd and Even Numbers
Even numbers are easily divisible by two (includes 0). Odd numbers are not easily divisible by 2.
Even+Even=Even
Odd+Odd = Even
Even + Odd = Odd
Even x Even = Even
Odd x Odd = Odd
Even x Odd = Even
Factor
Any natural number that that divides into a another number without a remainder.
Example: The factors of 18 are 1, 2, 3, 6, 9, and 18
Multiple
The value that results when multiplying a given number by any natural number.
Example: the multiples of 3 include 3, 6, 9, 12, 15….
Absolute Value
The magnitude of a number without regard to its sign. The distance between zero and any number on a number line is the absolute value of that number (always positive).
Example: |4| = 4 and |-4| = 4
The Rules of Absolute Value
- |-a| = |a|
- |a|>=0 (the only situation in which |A|=0 is when A=0)
- |a/b| = |a| / |b| (b cannot equal 0)
- |ab| = |a| x |b|
- |a^n| = |a|^n