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Knowledge base
More explainers from the knowledge base. Each one names what you need to know first, works through the method, and says where it usually goes wrong.
Examples FractionsFraction Examples: 10 Worked Problems With AnswersTen problems, worked in full. They are ordered so each one adds exactly one new difficulty to the last.
Mistakes Fractions5 Common Fraction Mistakes and How to Catch ThemEvery one of these has a ten-second check. Learning the checks is faster than learning to never make the mistake.
Distinction FractionsMixed Number vs Improper Fraction: Which to UseTwo ways of writing the same quantity. One is easier to picture, the other is easier to calculate with — and questions expect you to move between them.
Application FractionsFractions in Real Life: Where They Actually Turn UpFractions did not survive because schools like them. They survive because for halving, sharing and measuring, they are simply better than decimals.
Concept AlgebraWhat Is the Quadratic Formula? Where It Comes FromOne formula solves every quadratic there is. It is worth knowing why, because the reason is also the method it replaces.
Method AlgebraHow to Use the Quadratic Formula: Step by StepFive steps, in order. Four of the five mistakes people make happen in the first two.