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Unformatted text preview: SAT Math Facts & Formulas Numbers, Sequences, Factors Integers: . . . , 3, 2, 1, 0, 1, 2, 3, . . . Reals: integers plus fractions, decimals, and irrationals ( √ 2, √ 3, π , etc.) Order Of Operations: PEMDAS (Parentheses / Exponents / Multiply / Divide / Add / Subtract) Arithmetic Sequences: each term is equal to the previous term plus d Sequence: t 1 , t 1 + d , t 1 + 2 d , . . . The n th term is t n = t 1 + ( n − 1) d Number of integers from i n to i m = i m − i n + 1 Sum of n terms S n = ( n/ 2) · ( t 1 + t n ) (optional) Geometric Sequences: each term is equal to the previous term times r Sequence: t 1 , t 1 · r , t 1 · r 2 , . . . The n th term is t n = t 1 · r n − 1 Sum of n terms S n = t 1 · ( r n − 1) / ( r − 1) (optional) Prime Factorization: break up a number into prime factors (2, 3, 5, 7, 11, . . . ) 200 = 4 × 50 = 2 × 2 × 2 × 5 × 5 52 = 2 × 26 = 2 × 2 × 13 Greatest Common Factor: multiply common prime factors 200 = 2 × 2 × 2 × 5 × 5 60 = 2 × 2 × 3 × 5 GCF(200 , 60) = 2 × 2 × 5 = 20 Least Common Multiple: check multiples of the largest number LCM(200 , 60): 200 (no), 400 (no), 600 (yes!) Percentages: use the following formula to find part, whole, or percent part = percent 100 × whole www.erikthered.com/tutor pg. 1 SAT Math Facts & Formulas Averages, Counting, Statistics, Probability average = sum of terms number of terms average speed = total distance total time sum = average × (number of terms) 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. (Extend this for three or more: N...
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This note was uploaded on 01/10/2011 for the course EE 100 taught by Professor Razasuleman during the Spring '10 term at University of Engineering & Technology.
 Spring '10
 RazaSuleman

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