Number Properties Flashcards
divisibility
An integer is divisible by 2 if…
the integer is even
divisibility
An integer is divisible by 3 if…
if the SUM of the integer’s digits is divisible by 3
divisibility
An integer is divisible by 4 if…
if the integer is divisible by 2 TWICE or if the LAST TWO digits are divisible by 4
divisibility
An integer is divisible by 5 if…
if the integer ends in 0 or 5
divisibility
An integer is divisible by 6 if…
the integer is divisible by both 2 and 3
divisibility
An integer is divisible by 8 if…
the integer is divisible by 2 THREE TIMES or if the LAST THREE digits are divisible by 8
divisibility
An integer is divisible by 9 if…
the SUM of the integer’s digits is divisible by 9
divisibility
An integer is divisible by 10 if…
if the integer ends in 0
divisibility
Factor Foundation Rule
If a is a factor of b, and b is a factor of c, then a is a factor of c
Ex. 2 is a factor of 6 and 6 is a factor of 72, then 2 is a factor of 72
odds and evens
even + even or even - even
even
odds and evens
even + odd or even - odd
odd
odds and evens
when multiplying integers, if ANY integer is even, the result will be
even
odds and evens
when multiplying integers, if ALL of the integers are odd, the result will be
odd
odds and evens
even/even
even, odd, or non-integer
odds and evens
even/odd
even or non-integer
odds and evens
odd/even
non-integer
odds and evens
odd/odd
odd or non-integer
divisibility
3^k means
How many 3s are there
example question: p is 30! what is the largest integer k when 3^k is a factor of p
Perfect squares
Perfect squares have a … number of total factors
Odd
Perfect squares
Prime factorization a contains only … of primes
Even powers
Ex 144 = 223*3
