The Number System Flashcards
Real numbers
All numbers that can be found on a number line. Includes large or small numbers, positive or negative numbers, decimals, fractions, etc. Ex. 5,-7, 1/2, pi, Square root of two
Irrational numbers
Numbers that cannot be written as a simple fraction because the decimal goes on forever without repeating. Ex. 3.141592665…
Rational numbers
Any number that can be written by dividing one integer by another. A fraction or ratio. Rational’s root word is ratio
Integer
All whole numbers including positive and negative numbers
Whole numbers
All numbers with no fractional or decimal part. Cannot be negative.
Natural numbers
Whole numbers from one and up. These are all the counting numbers.
Positive numbers
Describe quantity is greater than zero
Negative numbers
Describe quantities less than zero
Opposites
Positive and negative signs are called opposites, so +5 and-5 are also called opposites.
Opposites of opposites property
The opposite of the opposite of a number is the number itself
Absolute value
The absolute value of a number is it’s a distance from zero (on the number line). Thus, the absolute value is always positive. We indicate absolute value by putting two bars around the number. Absolute value bars are also grouping symbols, so you must complete the operation inside them first, then take the absolute value. A number in front of the absolute value bars means multiplication.
Factors
Factors are integers you multiply together to get another integer.
Prime number
A prime number is a number that has only two factors (the number itself and 1). Some examples of prime numbers are 2, 3, 5, 7, and 13).
Common factors
Any factors that are the same for two (or more) numbers are called common factors.
Greatest common factor (GCF)
The largest factor that both numbers share is called the greatest common factor or GCF for short
