SAT Arithmetic Reminders
CMT
- Statistical terms:
o Range: difference between the largest and smallest
o Mode: the term which occurs most frequently
o Median: the middle term after the list has been arranged from
smallest to largest.
o Mean: the average; find the sum of all the terms, then divide
by the number of terms
- Other terms:
o Factors: divides a number without a remainder
o Multiples: the numbers increasing by a common difference
(Example: the multiples of 4 are 4, 8, 12, 16, 20, 24, …
o Prime: numbers divisible by only 1 and itself
o Consecutive numbers:
 Consecutive integers – x, x+1, x+2, x+3, …
 Consecutive even or odd integers – x, x+2, x+4, x+6, …
- Percent:
o
o
o
is
%

of 100
part
%

whole 100
increase / decrease %increase / decrease

start  value
100
o Tip is normally considered 15%.
- PEMDAS
SAT Algebra Facts
CMT
- Solving systems:
o Substitution
o Elimination
- Given 1 Expression and 1 Equation, evaluate the value of the
expression
o Need to make the expression (the one without the equal sign to
look like the equation.)
o Use Algebra to accomplish this
o If x + y = 6, then 2x + 2y = 12
- Combine like terms carefully; check the exponents made sure that
they are really like terms
- Average speed =
TotalDis tan ce
TotalTime
- Inequalities:
o Solve as if the inequality is like an equal sign.
o Make sure when you multiply or divide each side by a negative,
that you flip the sign.
- Slope
o
o
o
o
o
o
y2  y1
=slope
x2  x1
y = mx + b; where m is the slope
Parallel lines have equal slopes.
Perpendicular lines have slopes which are opposite reciprocals.
Horizontal lines have a slope of 0.
Vertical lines have an undefined slope or no slope.
SAT Discrete Discussion
CMT
- Fundamental Counting Principle:
o Number of outfits or choices
o Things are separate such as choose top has nothing to do with
choosing pants
- Permutations:
o Order matters.
o Situations include: sitting people at a table, telephone numbers,
pick-3; choosing a person for president and vice-president
o
n
Pr 
n!
(n  r )!
- Combinations
o Order does not matter.
o Situations include: Pick-6 Lottery, choosing two people to
represent the class, choosing three toppings for your pizza,
o
n
Pr 
n!
r !(n  r )!
- Probability:
Total # successes
Total # possibilities
AreaOfSuccessful Re gion
o Geometric Probability =
EntireArea
o Probability =
- Series:
o Pattern repeating:
 1,5,6,7,8,1,5,6,7,8,…
 Divide term wanted by number of items in pattern.
The remainder represents the term which is the
answer
 Find the units digit of 340 .