Number Properties Flashcards
PEMDAS “ Please Excuse My Dear Aunt Sally”
Parentheses
Exponents
Multiplication
Division
Addition
Subtraction
Commutative Law of Addition and Multiplication
Addition and multiplication are both commutative, which means that switching the order of any two numbers being added or multiply together does not affect the result.
division and subtraction, or not commutative .
Associative Laws of Addition and Multiplication
Regrouping the numbers does not affect the result.
Distributive Law of multiplication allows you to distribute a factor over numbers are added or subtracted.
a (b + c) = ab + ac
The law works for numerator:
a + b / c = a/c + b/c , but does not work when the sum or difference is in the denominator.
9/ 4 + 5 is not equal to 9/4 + 9/5
Division by zero is undefined. Any fraction with zero in the denominator is also undefined.
Multiples and Divisibility
A multiple is the product of a specified number and an integer. Multiples do not have to pee of integers, but all multiples must be of the product of a specific number and an integer. The concepts of multiples and factors are tied together by the idea of divisibility a number that is evenly divisible by a second number is also a multiple of the second number.
1) An integer is divisible by 2 if its last digit is divisible by 2.
2) An integer is divisible by 3 if its last digits add up to the multiple of 3.
3) An integer is divisible by 4 of its last digits are multiple 4.
4) An integer is divisible by 5 if its last digit is 0 or 5.
5) An integer is divisible by 6 if it is divisible by both 2 and 3.
6) An integer is divisible by 9 if its digits add up to a multiple of 9.
Rules for Odds and Evens
Odd + Odd = Even
Even + Even = Even
Odd + Even = Odd
Odd + Odd = Odd
Even + Even = Even
Odd + Even = Even
A prime number is an integer greater than 1. It has only two factors: itself and 1. The number 2 is the smallest prime number and the only even prime.
First ten prime numbers: 2, 3, 5, 7, 11, 13, 17, 19, 23, and 29.
