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Welcome to Math 20!

Our syllabus describes the class calendar, homework, grading, and other important information.

link to syllabus

Mastering new math ideas ultimately involves changing how we think and practicing thinking critically. These have been called the two keys to student success.

Therefore the process of learning our math topics is like a chair that stands on four legs: turning lectures into helpful lecture notes, dilligently doing both "prompt" and "enough" homework problems, developing good test-taking techniques, and rehearsing careful step-by-step work on practice tests. Neglecting any of these four is dangerous! Please do not demonstrate such recklessness. Successful students make time for all four.

You can see your grades for the review days.

You can see your grades for chapters 5 and 6 (ratio and percent).

Online Lecture Notes


Concepts: Understanding Division, Factors, Rounding, Estimating, Exponents, The Perils of PEMDAS, Terms, Negative Numbers

Skills: Divisibility Rules, Finding Factors, Decimal Point Scoots, One-Step Equations, Shoes and Socks

Review Problems



Concepts: Desired Denominators, Fraction Multiplication and Division, The Six Step Problem Solving Method

Skills: Addition and Subtraction, Subtracting Mixed Numbers, Changing Fractions to Decimals, Changing Decimals to Fractions

Review Problems


Ratio, Rate, and Proportion

Concepts: Four Definitions

Skills: Writing and Simplifying Ratios, Multiply in an X Shape, Proportions with Variables, Word Problems, Scaling



Concepts: As a Rating Scale, Shortcuts

Skills: Percents, Decimals, and Fractions, Percent Sentences, Word Problems, Simple Interest, Percent Change, Approaching Formulas, The One Plus Trick, The Fraction Trick



Concepts: Measurement Units, History, One Step Conversions, Conversion Rates, Parts of a Gallon, Square Roots

Skills: Unit Analysis, Temperature Conversions, More About SI Prefixes



Concepts: Perimeter, Area Formulas, Square Units, Pi

Skills: Polygon Area Puzzles, Measured Sides, Problem Solving Steps, Circle Puzzles



Test 1 — Arithmetic and Fractions (Chapters 1 to 4)

Test 2 — Ratio and Percent (Chapters 5 and 6)

Test 3 — Measurement and Geometry (Chapters 8 and 9)

Test 4 — Final Exam

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