Final Exam Flashcards
Divisibility rule: 2 only if
if the last digit is even (ends in 0, 2, 4, 6, 8…)
Divisibility rule: 3
The sum of the digits is divisible by 3
Divisibility rule: 4
The last 2 digits are divisible by 4
Divisibility rule: 5
The last digit is a 0 or 5
Divisibility rule: 6
The number is divisible by 2 and 3
Divisibility rule: 8
The last 3 digits are divisible by 8
Divisibility rule: 9
The sum of digits is divisible by 9
Divisibility rule: 10
The last digit is a 0
Divisibility rule: 11
if the difference of the sum of digits is 0 or 11
Arithmetic sequence formula
an = a1 + (n-1)d
Proper subset
a subset that contains all the elements of another set, but is not the same set itself (ex. If A = {1, 2, 3} and B = {1, 2}, then B is a proper subset of A because all elements of B are in A, but A has an additional element (3) not present in B.)
(written out answer ex. 2^6 - 1)
Improper subset:
a subset of a set that contains all the elements of the original set, meaning it is essentially the original set itself; every set only has one improper subset, which is the set itself.
(Ex. if set A = {1, 2, 3}, then the only improper subset of A is A itself, {1, 2, 3}.) (Written out answer ex. 2^6)
Closure property of addition of whole numbers
the sum of two whole numbers is a unique whole number; for example, 5+2 is a unique whole number, and that number is 7
Closure property of multiplication of whole numbers
when two numbers from a set are multiplied, the product is also in that set
Prime numbers
natural numbers that are divisible by only 1 and the number itself.
examples: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, …
