Groups of Numbers Flashcards
Natural or Counting Numbers
the numbers 1, 2, 3, 4
whole numbers
the numbers 0, 1, 2, 3, 4. whole numbers are counting numbers plus 0
Integers
The numbers -1, -2, 0, 1, 2
Negative Integers
The numbers -3, -2, -1
Positive Integers
The natural numbers are sometimes called positive integers
Rational Numbers
The numbers that can be expressed as fractions using integers are called rational numbers. Values such as 1 1/2 = 3/2 or 0.875 = 7/8 are called rational numbers. Since every integer can be expressed as that integer over 1, all integers are rational numbers. Zero is a rational number since 0/1 = -
Irrational numbers
the numbers whose exact values cannot be expressed as fractions are called irrational numbers. Two examples of irrational numbers are sqrt of 3 and pi
Real numbers
real numbers consist of all rational and irrational numbers. typically, most standardized exams use only real numbers, which are commonly used numbers in everyday math calculations
Prime numbers
a prime number is a natural number greater than 1 that can be evenly divided only by itself. for example, 19 is a prime number because it can be evenly divided only by 19 and 1, but 21 is not a prime number because 21 can be evenly by other number (3 and 7). the only even prime number is 2; thereafter any even numbermay be divided evenly by 2. therefore any even number greater than 2 is not a prime number. zero and 1 are not prime numbers
what are the first 10 prime numbers
2, 3, 5, 7, 11, 13, 17, 19, 23, 29
composite number
A composite number is a natural positive number greater than 1 and divisible by more than just 1 and itself. 4, 6, 8, 9, 10, 12, 14, 15
odd numbers
are integers not divisible by 2
even numbers
even numbers are integers divisible by 2
squares
squares are the result when numbers are raised to the second power
cubes
cubes are the result when numbers are raised to the third power
