
Whole Numbers are basic numbers used for counting. For example, 0, 1, 2, 124, 4297... Whole numbers are:
 From zero up to infinity (positive)
 Positive (except for zero, which has some special rules and considerations.)
 Never a fraction
 Never contain a decimal

Integers: Just like whole numbers, but also includes negatives. Some examples are 4, 3, 416, and also 0, 1, 2, etc. Integers are:
 Negative or positive up to infinity
 Only "counting numbers"
 Never a fraction
 Never contain a decimal

Odd Numbers: Examples are 1, 5, 9, 11, as well as their negatives 1, 5, 9 and so on. Odd numbers are
 Always positive or negative
 Only Integers (no decimals or fractions)
 Not divisible by 2 evenly.

Even Numbers: Examples are 0, 2, 4, 8, and so on into infinity. There are even negative numbers as well. Even numbers are
 Always positive or negative
 Only integers (no fractions or decimals)
 Always evenly divisible by two (2_)
 Consecutive: When you see this word on the SAT math section, it simply means something  "in a row." For example an SAT question might ask for "three consecutive numbers" (like 7, 8, 9) although they may also ask for more specifics like "four consecutive odd numbers." Because of this, it is important to not assume right away when the word consecutive is seen. Instead, reading the question carefully and understanding what is being asked for will increase the chances of successfully answering the question and getting points for a high math score on the SAT. It should also be noted that consecutive numbers will be integers.
TIP: Test takers should remember that "consecutive numbers" will be integers. Having said that, there are cases the integers may be in an odd location (like a fraction), but as long as the question is read carefully, this will be explained and understood.
BONUS TIP: If a question on the SAT math section asks for "four consecutive numbers" and the question requires algebra to solve, set up the equation to use X as the smallest number. The next number will be x + 1, then x + 2 and so on for every consecutive number. If the question asks for consecutive even numbers or consecutive odd numbers, set up x for the smallest number, but then use x + 2 for the second number, x + 4 for the third number, and so on. Even for consecutive odd numbers, you still use x + 2, x + 4, and so forth. Plug a number in to further see how this works.
 Real Numbers: These are all numbers in existence except for imaginary numbers. The explanation is simple, but occasionally test takers will read too much into the question asking for a "real number" and miss the whole point of the question, getting it wrong and lowering the overall SAT math score.

Rational Numbers: These are "any number that can be written as x / y where x and y are integers." To further explain...
 A rational number will be a repeating decimal like .99, a terminating decimal like .324, or a fraction  2/9 or 43 / 7
 In algebra problems, if the question specifies that the variable will be an integer, something like 5/x would be a rational number.
 Irrational numbers are ones like π or √2  numbers that do not end and cannot be written as fractions.
 Positive Numbers: These are simply numbers that are greater than zero, reaching to infinity.
 Negative Numbers: These are numbers that are less than zero  again to infinity in this direction.
 Digits: These are the basic numbers 0 through 9. Digits are like the numbers on a cellphone. A sample question might ask "When a fourdigit number is added to a two digit number, the result will always be …" The answer will be one of the digits 0 through 9.
 Distinct: Distinct numbers are "separate" or "different" than others. If a question asks, "In a fraction where x and y are both distinct integers, what happens when..." So, the test makers are looking for two separate numbers, not the same one for both x and y.
 Divisible: This means a number can be evenly divided. For example, 49 is divisible by 7 without a remainder.
 Divisor: This is the number that will go into the other number. For example, in the equation "36 ÷ 4" the divisor would be the number 4. Some refer to this as the number "outside the bridge" when doing long division. On the other hand, the dividend is the number "under the bridge."
 Sum/Difference/Product/Quotient: These are the answers for math. The sum is for addition problems, the difference uses subtraction, the product is found with multiplication, and the quotient is found using division.

Special Rules for the number zero (0)
 Zero is NOT positive OR negative
 Zero is an even number
 Zero is a real, rational, integer.
 Zero is a whole number, and a digit
 Zero is a multiple of every number
 Anything multiplied by zero is zero
 Parentheses
 Exponents
 Multiply
 Divide
 Add
 Subtract
 Parentheses
 Exponents
 Multiply/Divide
 Add/Subtract