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Integers:
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. . . , -3, -2, -1, 0, 1, 2, 3, . . .
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Rationals:
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fractions, that is, anything expressable as a ratio of integers
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Reals:
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integers plus rationals plus special numbers such as √2, √3 and
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Order Of Operations:
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PEMDAS (Parentheses / Exponents / Multiply / Divide / Add / Subtract)
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Arithmetic Sequences:
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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, . . .
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Geometric Sequences:
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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, . . .
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Factors:
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the factors of a number divide into that number without a remainder
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Multiples:
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the multiples of a number are divisible by that number without a remainder
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Percents:
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use the following formula to find part, whole, or percent part = percent 100 × whole
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average
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average = sum of terms number of terms
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average speed
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total distance/total time
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sum
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Average*number of teerms
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mode
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value in the list that appears most often
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median
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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
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Fundamental Counting Principle:
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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.
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SAT Prep
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Cheatography n. The art of mapping complex subjects into clear, instantly navigable reference guides.
