GRE Studying

what is the formula for permutations of indistinguishable items?

(N!)/ ((r1!)(r2!)(rn!))

The number of ways to arrange a set of items in a circle is the following formula:

(k-1)!

median formula in odd # of terms:

(n+1)/2 position

(x^a)/(y^a)

(x/y)^a

Perfect Squares to Memorize

0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225

Perfect Cubes to Memorize

0, 1, 8, 27, 64, 125, 216, 343, 512, 729, 1,000

2^0

1

In a probability space, the probabilities must sum to

1

The GCF of any two consecutive integers is _______

1

When a nonzero base is raised to the zero power, the expression equals

1

Square root of 2

1.4

Square root of 3

1.7

4^5

1024

How many edges does a cube have?

12

5^3

125

2^7

128

2^4

16

4^2

16

2^1

2

What are the prime numbers less than 100?

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

Square root of 5

2.2

4! = ?

24

3^5

243

5^2

25

2^8

256

4^4

256

3^3

27

2^n + 2^n

2^(n+1)

3^1

3

2^5

32

3^n + 3^n + 3^n

3^(n+1)

2^2

4

4^1

4

4^n + 4^n + 4^n + 4^n

4^(n+1)

5^1

5

2^9

512

5^4

625

2^6

64

4^3

64

2^3

8

3^4

81

3^2

9

What is the distance formula

Distance = Rate x Time

What is the 'percent less than' formula?

Final = (1-(percent/100)) x initial

when n is added / subtracted to every number in the dataset, what happens to the IQR

IQR2 = IQR1

What is the basic probability formula?

P = (favorable # of outcomes) / (Total # of outcomes)

If A and B are not independent, what is the formula for P(A and B)

P(A and B) = P(A) * P(B | A)

If A and B are independent, what is the formula for P(A and B)

P(A and B) = P(A) * P(B)

When events are mutually exclusive, P(A or B) =

P(A) + P(B)

What is the formula for complementary events

P(a) + P(not a) = 1

when n is multiplied/ divided by every number in the dataset, what happens to the standard deviation

SD2 = SD1 *n

What is a multiple?

The product of that number and any integer

What is independence in probability?

Two events are independent when the incidence of one event does not affect the probability of the other event occuring

a to b is equivalent to

a/b

a is what percent of b translates to

a/b * 100 = ?

median formula in even # of terms:

average of n/2 and (n+2)/2 position

1 to a/b is equivalent to

b to a

sqrt(a+b) _______ sqrt(a) + sqrt(b)

does not equal

A perfect square will have only _______ exponents of its prime factorization

even

even + even

even

even - even

even

even x even

even

even x odd

even

odd + odd

even

odd - odd

even

odd x even

even

an open circle means that value is ___________

excluded

formula to calculate range

highest number in a set - lowest number in a set

mean = median when

in any evenly spaced set, the mean of the set is equal to the median of the set

a closed circle means that value is ___________

included

when n is multiplied/ divided by every number in the dataset, what happens to the mean

mean2 = mean1 *n

when n is added / subtracted to every number in the dataset, what happens to the mean?

mean2 = mean1 +- n

when n is multiplied/ divided by every number in the dataset, what happens to the median

median2 = median1 *n

when n is added / subtracted to every number in the dataset, what happens to the median

median2 = median1 +- n

when n is multiplied/ divided by every number in the dataset, what happens to the mode

mode2 = mode1 *n

when n is added/ subtracted to every number in the dataset, what happens to the mode

mode2 = mode1 +- n

what is a mode

most frequently occurring value

what is the basic combination formula

n! / ((n-k)!k!)

what is the basic permutation formula

n! / (n-k)!

in the equation (n/k) what is n

number of objects

in the equation (n/k) what is k

number of objects selected

What is a factor?

numbers you multiply together to get another number

even + odd

odd

odd x odd

odd

when n is multiplied/ divided by every number in the dataset, what happens to the range

range2 = range1 *n

when n is added / subtracted to every number in the dataset, what happens to the standard deviation

sd2 = sd1

non-perfect squares to memorize

square root of: 2, 3, 5

formula for average

sum of terms / number of terms

In the formula (k-1)! what is k?

the number of terms to be arranged in a circle

A perfect cube will have only exponents divisible by _______ in its prime factorization

three (3)

x is n percent of y

x = (n/100)*y

x percent of z translates to

x/100 * (z)

(x^a)(x^b)

x^(a+b)

(x^a)/(x^b)

x^(a-b)

b-root(x^a)

x^(a/b)

(x+y)^2

x^2+2xy+y^2

(x-y)^2

x^2-2xy+y^2

(x^a)^b

x^ab

(x+y)(x-y)

x²-y²