Jump to a New ChapterIntroductionThe Discipline of DisciplineSAT StrategiesThe SAT Personal TrainerMeet the Writing SectionBeat the EssayBeat Improving SentencesBeat Identifying Sentence ErrorsBeat Improving ParagraphsMeet the Critical Reading sectionBeat Sentence CompletionsReading Passages: The Long and Short of ItThe Long of ItThe Short of ItSAT VocabularyMeet the Math SectionBeat Multiple-Choice and Grid-InsNumbers and OperationsAlgebraGeometryData, Statistics, and Probability
 18.1 Know Your Numbers 18.2 Order of Operations 18.3 Odd and Even Numbers 18.4 The Positive, the Negative, and the Ugly 18.5 Divisibility and Remainders 18.6 Factors 18.7 Multiples 18.8 Know Your Fractions

 18.9 Decimals 18.10 Percents 18.11 Ratios 18.12 Exponents 18.13 Roots and Radicals 18.14 Sequences 18.15 Sets
Odd and Even Numbers
Even numbers are numbers that are divisible by 2 with no remainder. Remember that zero is included within this definition.
Even Numbers: . . . , –6, –4, –2, 0, 2, 4, 6, . . .
Odd numbers are numbers that, when divided by 2, leave a remainder of 1.
Odd Numbers: . . . , –5, –3, –1, 1, 3, 5, . . .
Operations and Odd and Even Numbers
For the SAT, you have to know how odd and even numbers act when they’re added, subtracted, multiplied, and divided. The chart below shows addition, subtraction, and multiplication because multiplication and division are the same in terms of odd and even.
Addition Subtraction Multiplication Even + Even = Even Even – Even = Even Even × Even = Even Odd + Odd = Even Odd – Odd = Even Odd × Odd = Odd Even + Odd = Odd Even – Odd = Odd Even × Odd = Even
If you know how odd and even numbers act when put through any of the four operations, you have a leg up in using the process of elimination. If the numbers in the answer choices are both odd and even, you should be able to use the rules of odd and even numbers to figure out if the answer you’re looking for is odd or even. So even if you don’t know the exact value of the answer you’re looking for, you should be able to eliminate half of the answers based on whether they’re odd or even.
 Jump to a New ChapterIntroductionThe Discipline of DisciplineSAT StrategiesThe SAT Personal TrainerMeet the Writing SectionBeat the EssayBeat Improving SentencesBeat Identifying Sentence ErrorsBeat Improving ParagraphsMeet the Critical Reading sectionBeat Sentence CompletionsReading Passages: The Long and Short of ItThe Long of ItThe Short of ItSAT VocabularyMeet the Math SectionBeat Multiple-Choice and Grid-InsNumbers and OperationsAlgebraGeometryData, Statistics, and Probability
Test Prep Centers
 New SAT Test Center Mini SAT
SAT Vocab Novels
 Rave New World S.C.A.M. Sacked Busted Head Over Heels
SAT Power Tactics
 Algebra Data Analysis, Statistics & Probability Geometry Numbers & Operations Reading Passages Sentence Completions Writing Multiple-Choice Questions The Essay Test-Taking Strategies Vocabulary Builder
SparkCollege
 College Admissions Financial Aid College Life