GMAT REVIEW
Read pgs. 43-44 before exam
MATH REVIEW
ALGEBRA
Integers: whole or natural numbers; can be negative or positive but do not include fractions
(3,2,1,0,-1,-2)
Positive and Negative Numbers:
+ * + = +
+ * - = -
- * - = +
Digits: All intefers are made up of digits. In the integer 246 there are 3 digits: 2,4,6. Each of the
digits has a different name: 6=unit or one digit, 4= tens digit, and 2= hundreds digit.
27.63 =>
2=tens digit, 7= units digit, 6= tenths digit an 3=hundredth digit
Odd/Even: Even numbers are integers that can be divided evenly by 2, leaving no remainder (-6,
-4, -2, 0, 2,4,6) . Odd numbers are integers that cannot be divided evenly by 2 (-5, -3,-1, 1, 3, 5).
Even*even=even
odd*odd=odd
even*odd=even
even + even=even
odd+odd=even
even +
odd= odd
Consecutive Integers: are integers listed in order of increasing value without any integers
missing in between -3, -2, -1, 0, 1, 2, 3
Distinct numbers: if 2 numbers are distinct, they cannot be equal
Prime numbers: positive integer that is divisible only by 2 numbers: itself and 1
Divisibility Rules: if there is no remainder when integer x is divided by integer y, then x is said
to be divisible by y.
Prime Factors: if an integer, x, that is a factor of an integer, y, is also prime then x is called a
prime factor of y.
12
12
3
4
2
6
2
2
3
2
Average or mean= total sum of items/ total number of the items
Median (middle number)
=
4, 7 ,
12, 14, 20
4, 12, 14, 20 => (12+14)/2=
13
Mode= pick the number that is repeating the most: 5, 6, 3, 9, 3, 28, 3, 5 =>
3
Range= 4, 3, 8, 12, 23, 37 = 37-3 =
34
Exponents:
Multiply numbers with the same base:
6^2 * 6^3 = 6^ 5
Dividing numbers with the same base: 6^5 * 6^3 = 6^2
Raising a power to a power: (4^3)^2 = 4^6
Distributing exponents: (4y)^2 = 4^2 * y^2 = 16y^2
Radicals:
√x
*
√y
= √xy
√x/y
= √x /√y
Distance= Rate * Time
Probability Formula =
# of outcomes you want / total # of possible outcomes
=
Probability that A or B will happen : A+B
= The odds that something doesn’t happen:
Won’t = 1 – Will
n(n-1)(n-2)….*(n-r+1)
=>
n!
=>
9*8*7*6*5
r!
r!(n-r)!
4*3*2*1