Integers Flashcards

1
Q

integer

A

a number that can be written withut a decimal or fractional component

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2
Q

whole numbers

A

inonnegative integers and 0

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3
Q

properties of 0

A
0x any number=0
0/any numb=0
any numb / 0= undefined (not 0) 
square root of 0 is 0
0^2 =0
0 is the only number that is equal to its opposite (0=-0)
0= multiple of all numbers
0 is even number
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4
Q

properties of 1

A

1^2= 1
1 is odd number
1 is not a prime number

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5
Q

even and odd numbers

A
even= a number must be divisible by 2 without leaving a remainder 
units digit= 0,2,4,6,8
can be represented as= 2n
odd=if it's not divisible by 2 
units digit= 1,3,5,7,9
can be represented as 2n-1 or 2n+1
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6
Q
odd+odd=
even+even=
even+odd=
odd-odd=
even-even=
odd-even=
even-odd=
A
odd+odd=even
even+even=even
even+odd=odd
odd-odd=even
even-even=even
odd-even=odd
even-odd=odd
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7
Q

eveneven
even
odd
oddeven
odd
odd

A

eveneven=even
even
odd= even
oddeven= even
odd
odd= odd

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8
Q

even/odd
odd/odd
even/even

A

even/odd=even
odd/odd=odd
even/even=even or odd

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9
Q

absolute values

A

is a distance from zero on a number line (hence both -5 and 5 are on the same distance from 0)

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10
Q

signed numbers

A

another way to refer to a positive or negative number

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11
Q

+++=

—=

A

+

-

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12
Q

multiplying or dividing two numb with the same sign

A

the result (product or quotient) is always positive

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13
Q

multiplying or dividing two numb with the different sign

A

the result (product or quotient) is always negative

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14
Q

when a nonzero base is raised to an even exponent

A

the result will always be positive

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15
Q

when a nonzero number is raised to an odd exponent

A

if the original base is positive the result will be positive

if the original base is negative the result will be negative

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16
Q

for any positive integers x and y , y is a factor of x if and only

A

if x/y is an integer

1<= y<=x –> the factors or divisors

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17
Q

multiple of a number

x is multiple of y if and only

A

is the product of that number with any integer
if x/y is an integer
x is a multiple of 5= x/5 is an integer

18
Q

Prime Numbers

A

any integer greater than 1 that has no factors other than 1 and itself
2 is the only prime number that is even, all the rest are odd

19
Q

first 30 prime numbers

A

2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97

20
Q

prime factorization

A

any composite number (a number that is not prime) can be broken down and expressed as the product of its prime factors

21
Q

finding the number of factors of a particular number (including both prime and non-prime factors)

A
  1. find the prime factorization of a number i.e 2,160 = 2^4 * 3^3 * 5^1
  2. add 1 to the value of each exponent and then multiply these results =(4+1)(3+1)(1+1)= 40
22
Q

unique prime factors

A

distinct/different prime factors a number contains

i.e 12= 223 and has 2 distinct prime factors

23
Q

the number of unique prime factors in a number does not change when

A

that number is raised to a positive integer exponent

24
Q

LCM

A

smallest positive integer into which all the numbers in set will divide
LCM of 2 and 5= 10

25
Q

how to find LCM

A
  1. prime factorization of each integer
  2. of any repeated prime factors take the largest one (3^2 and 3^3 choose the 3^3 one) if we are left with two of the same power (3^2 and 3^2) just take that number once
  3. of what is left take all the non repeated prime factors
  4. multiply together what you found in the steps 2 and 3
    = the result is the lcm
26
Q

when a set of positive int do not share same p.f. the lcm is calculated by

A

multiplying those numbers (7,6= 7*6=42)

27
Q

GCF (greatest common factor)

A

is the largest number that will divide evenly into all of the numbers in the set ( 8,12,16= 4)

28
Q

finding gcf

A

prime factorization of all numbers and then multiply the left column only up to the number that divides the entire set

29
Q

if the set has no common p.f. the gcf is

A

1

30
Q

if we know the lcm and gcf of two positive int (x and y) we know the product of x and y

A

i.e we have two +ve int x and y whose value we dont know, by knowing gcf and lcm we can multiply them together and get the product
xy= LCM(x,y)GCF(xy) or
lcm(x,y)= (X)
(Y)/GCF (x,y) and gcf(x,y)=(x)*(y)/lcm(x,y)

31
Q

if we know the lcm of the set we can find all

A

unique prime factors

32
Q

using lcm to solve repeating pattern questions

A

i.e. light L flashes every 32 sec and light M flashes every 12 sec. if both lights flash together at 8pm, when will be the next time they’ll flash together?
lcm of 12 and 32= 96 (sec) so it will flash again at 8:01:36pm

33
Q

divisibility

A

x/y= z +(no remainder) x is dividend (numerator), y is a divisor (denominator) and z is quotient (the result)

34
Q

two positive int x and y, x/y will yield an int if x is a multiple of y or if y is a factor of x

A
means the result will yield an int 
y is a factor of x 
y is a divisor of x 
y divides into x 
x is multiple of y 
x is dividend of y 
x is divisible by y
35
Q

if x is divisible by y, then x is also divisible by all of the factors of y

A

100/20 is an int (=5), the factors of 20 are 1,2,4,5,10,20 -> 100/1, 100/2, 100/4, 100/5, 100/10 will be integers

36
Q

divisibility of exponents with the same base

A

a^3/a^2= a^3-2= a

37
Q

if x,a,b=int and x is not 0, in order for a^x/a^y to be an int

A

x>=y

38
Q

if z is divisible by both x and y, then z must be divisible by

A

the lcm of x and y

39
Q

finding a number of multiples are there between two numbers

i.e. numb of multiples of 4 between 12 and 96 inclusive?

A

last multiple of x in the range - first multiple in the range / x +1
(96-12/4)+1=22

40
Q

product of 3 consecutive integer is always divisible by

A

6

41
Q

two consecutive integer will never share the same prime factors
what is their gcf

A

always 1