facts-and-formulas-2a - SAT Subject Math Level 1 Facts&...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: SAT Subject Math Level 1 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 http://www.erikthered.com/tutor pg. 1 SAT Subject Math Level 1 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 1 × N 2 × N 3 . . . ) Permutations and Combinations: The number of permutations of n things is n P n = n ! The number of permutations of n things taken r at a time is n P r = n ! / ( n- r )! The number of combinations of n things taken r at a time is n C r = n ! / ( ( n- r )! r ! ) Probability: probability = number of desired outcomes number of total outcomes The probability of two different events A and B both happening is P ( A and B ) = P ( A ) · P ( B ), as long as the events are independent (not mutually exclusive). If the probability of event A happening is P ( A ), then the probability of event A not happening is P (not A ) = 1- P ( A ). Logic (Optional): The statement “event A implies event B ” is logically the same as “ not event B implies not event A ”. However, “event A implies event B ” is not logically the same as “event B implies http://www.erikthered.com/tutor pg. 2 SAT Subject Math Level 1 Facts & Formulas event A ”. To see this, try an example, such as A = { it rains } and B = { the road is wet } ....
View Full Document

Page1 / 9

facts-and-formulas-2a - SAT Subject Math Level 1 Facts&...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online