Rules Flashcards
Rules of operation
PEMDAS (parentheses, exponents, multiplication, division, addition, subtraction)
Communicative Laws of Addition and Multiplication
switching any two numbers will not change the sum or product
Associative Laws of Addition and Multiplication
regrouping a set of numbers does not affect results (e.g. (a+b) + c = a + (b+c)
Distributive Laws of Multiplication
can distribute a factor over numbers that are added/subtracted (e.g. 4(3+7) = 4(3) + 4(7)
also works for numerator of a fraction (e.g. (a+b)/c = (a/c) + (b/c)
Multiple
the product of a specified number and an integer (e.g. -9, 21, and 300 are multiples of 3)
Factor
the number multiplied by another number to get a desired number (e.g. 3 and 4 are factors of 12)
How to determine if 3 is a factor of a given number
if the sum of the digits add to a multiple of 3
How to determine if 4 is a factor of a given number
if the last 2 digits are a multiple of 4
How to determine if 6 is a factor of a given number
if it is divisible by both 2 and 3
How to determine if 9 is a factor of a given number
if the digits add up to a multiple of 9
odd + odd =
even
even + even =
even
odd + even =
odd
odd * odd =
odd
even * even =
even
odd * even =
even
How does one find the greatest common factor between two numbers?
- break both integers into their prime factorizations
- multiply all the prime factors they have in common
e.g. 36 and 48
36 = (2)(2)(3)(3)
48 = (2)(2)(2)(2)(3)
GCF = (2)(2)(3) = 12
Least common multiple
smallest number that is a multiple of each integer
How does one find the least common multiple of two numbers?
- find prime factorization of each
- extract each prime number the maximum times it appears in any one of the factorizations
- multiply those numbers
e.g. LCM of 6 and 8
6 = (2)(3)
8 = (2)(2)(2)
LCM = (2)(2)(2)(3) = 24
What does one do when multiplying two identical bases with different exponents?
add the exponents together
e.g. (2^3)(2^5) = 2^8
What does one do when dividing two identical bases with different exponents?
subtract the exponents from each other
What does one do when raising a power to another power?
multiply exponents
What does one do when multiplying two different bases with the same exponents?
multiply the bases together; the exponent remains the same
What does a negative exponent symbolize?
a reciprocal of the positive
e.g. 2^-2 = 1/4
What does an exponent of 0 symbolize?
all numbers raised to the 0 = 1
What does one do when subtracting/adding like radicals?
subtract/add them like usual
What does one do when multiplying/dividing radicals?
multiply/divide the radical and number outside the radical separately
e.g. 6sqrt(5) * 4sqrt(3) = 24*sqrt(15)
When comparing fractions, what is an easy way to tell which is larger?
- multiply the numerator of the first fraction by the denominator of the second, and vise versa
- write number next to numerator
- largest number next to numerator indicates that fraction is largest
e.g. which is larger: 5/6 or 7/9?
59 = 45
67 = 42
5/6 is larger