Cheatography

# SAT Cheat Sheet Cheat Sheet by Suha

### Numbers, Sequences, Factors

 Integers: . . . , -3, -2, -1, 0, 1, 2, 3, . . . Rationals: fractions, that is, anything expres­sable as a ratio of integers Reals: integers plus rationals plus special numbers such as √2, √3 and  Order Of Operat­ions: PEMDAS (Paren­theses / Exponents / Multiply / Divide / Add / Subtract) Arithmetic Sequences: each term is equal to the previous term plus d Sequence: t1, t1 + d, t1 + 2d, . . . Example: d = 4 and t1 = 3 gives the sequence 3, 7, 11, 15, . . . Geometric Sequences: each term is equal to the previous term times r Sequence: t1, t1 · r, t1 · r2, . . . Example: r = 2 and t1 = 3 gives the sequence 3, 6, 12, 24, . . . Factors: the factors of a number divide into that number without a remainder Multiples: the multiples of a number are divisible by that number without a remainder Percents: use the following formula to find part, whole, or percent part = percent 100 × whole

### Averages, Counting, Statis­tics, Probab­ility

 average average = sum of terms number of terms average speed total distan­ce/­total time sum Averag­e*n­umber of teerms mode value in the list that appears most often median middle value in the list (which must be sorted) Example: median of {3, 10, 9, 27, 50} = 10 Example: median of {3, 9, 10, 27} = (9 + 10)/2 = 9.5 Fundam­ental Counting Principle: If an event can happen in N ways, and another, indepe­ndent event can happen in M ways, then both events together can happen in N ×M ways. SAT Prep SAT Prep

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