Math

Question 0

Rational Numbers

Answer 0

All numbers that can be expressed as the ratio of two integers (all integers & fractions).

Question 1

Real Numbers

Answer 1

All numbers on the number line; all the numbers on the GRE are real.

Question 2

Irrational Numbers

Answer 2

All real numbers that are not rational, both positive & negative (e.g. pie or the square root of -3).

Question 3

Integer

Answer 3

All numbers with no fractional or decimal parts: multiples of one.

Question 4

What does PEMDAS stand for?

Answer 4

Please Excuse My Dear Aunt Sally
P = Parentheses
E = Exponents 
M= Multiplication
D = Division 
A = Addition
S = Subtraction

Question 5

Commutative Law

Answer 5

Addition & multiplication are both commutative; it doesn’t matter in what order the operation is performed.
example: 5+8 = 8+5; 2×6 = 6 x2
Division and subtraction are not commutative.
example: 3-2 ≠ 2-3; 6/2 ≠ 2/6

Question 6

Associative law

Answer 6

Addition and multiplication are also associative; the terms can be re-gripped without changing the result. Example: (a+b) + c = a + (b+c);
& (a x b) x c = a x (b x c)

Question 7

Distributive law

Answer 7

The distributive lot of multiplication allows us to “distribute” a factor among the terms being added or subtracted. In general, a(b+c) = ab+ac.

Or with division: 3+5/2 = 3/2 + 5/2

Question 8

Factors

Answer 8

The factors, or divisors, of a number are the positive integers that evenly divide into that number.

Question 9

Greatest common factor or greatest common divisor

Answer 9

The greatest common factor, or greatest common devisor, is a pair of numbers that are the largest factors shared by the two numbers.

Question 10

2

Divisibility tests

Answer 10

A number is divisible by two if it’s last digit is divisible by two.

Question 11

3

Divisibility tests

Answer 11

A number is divisible by three if the sum of its digits is divisible by three.

Question 12

4

Divisibility tests

Answer 12

I number is divisible by four if it’s last two digits are divisible by four.

Question 13

5

Divisibility tests

Answer 13

A number is divisible by five if it’s last digit is zero or five.

Question 14

6

Divisibility tests

Answer 14

A number is divisible by six if it is divisible by both two and three.

Question 15

9

Divisibility tests

Answer 15

A number is divisible by nine if the sum of its digits is divisible by nine.

Question 16

10

Divisibility tests

Answer 16

A number is divisible by 10 if it’s lasted it is zero.

Question 17

12

Divisibility tests

Answer 17

A number is divisible by 12 if it is divisible by both three and four.

Question 18

Prime number

Answer 18

A number divisible by 1 & itself. A prime number is an integer greater than 1 that has no factors other than 1 and itself. The number 1 is not considered prime. The number 2 is the first prime number and the only even prime.

Question 19

Prime factorization

Answer 19

The expression of the number as the product of its prime factors. No matter how you factor a number, it’s prime factors will always be the same.
example: 36 = 2 x 2 x 3 x 3

Question 20

Rules for odds and evens

Odd + Odd =

Answer 20

Even

Question 21

Rules for odds and evens

Odd + Even =

Answer 21

Odd

Question 22

Rules for odds and evens

Even + Even =

Answer 22

Even

Question 23

Rules for odds and evens

Odd x Odd =

Answer 23

Odd

Question 24

Rules for odds and evens Odd x Even =

Answer 24

Even

Question 25

Rules for odds and evens Even x Even =

Answer 25

Even

Question 26

Average formula is ...

Answer 26

Average= sum/#

Question 27

Any number raised to the power of zero = ? 5⁰ = ?

Answer 27

1 (one) ``` 5⁰ = 1 9⁰ = 1 ```

Question 28

What must you do when you multiply or divide both sides of an inequality by a negative number?

Answer 28

You must flip the inequality sign.

Question 29

How is -1 unique when raised to a power?

Answer 29

-1 = 1 when raised to any even power. & -1 = -1 when raised to any odd power.

Question 30

What happens to 0 & 1 when they are raised to any power?

Answer 30

They remain exactly the same.

Question 31

What is a negative exponent?

Answer 31

The rule for negative exponents is that they're equal to the reciprocal of the of the corresponding opposite power. example: 2² = 4, but 2﹣² = 1/4

Question 32

Average Speed = ?

Answer 32

Average Speed = Total Distance --------------- Total Time

Question 33

Area of a triangle = ?

Answer 33

Area = 1/2 • base • height

Question 34

What us Zero (0) raised to any power?

Answer 34

Zero raised to any power is still zero.

Question 35

What happens to an inequality symbol when the inequality is multiplied or divided by a negative number?

Answer 35

The inequality symbol is reversed.

Question 36

Distance formula

Answer 36

d=rt ``` d = distance r = rate t = time ```

Question 37

The formula for the computation of simple interest

Answer 37

I = Prt ``` I = the interest P = the principal r = the annual rate expressed as a decimal t = time expressed in years ```

Question 38

To compute the amount, A, of an investment, P, at the end of two years, at annual rate, are, use the formula

Answer 38

A = P(1+rt)

Question 39

To compute the amount of an investment, A, involving compound interest, use the formula:

Answer 39

A = P(1 + r/C) to the power of tC A=the investment C = the Number of times compounded annually r = and you're already expressed as a decimal t= Time in years

Question 40

How do you solve for the X – intercept?

Answer 40

``` To solve for the X – intercept, simply set Y to zero in the equation for the line, and solve for X. 4x + 3y = 12 4x + 3(0) = 12 4x = 12 4x/4 = 12/4 X = 3 ```

Question 41

How do you solve for the Y – intercept?

Answer 41

Simply set X to zero and solve for Y. ``` 4x + 3y = 12 4(0) + 3y = 12 3y = 12 3y/3 = 12/3 Y = 4 ```