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Lessons by Ms Lam
Ms Lam specialises in percentages, ratio and reverse-percentage problems. Her drills mirror the wording students meet in school tests and TSA-style papers.
Rational numbers: fractions, decimals and recurring decimalsConvert between fractions and decimals, recognise recurring decimals, and keep rational arithmetic organised.Numbers & Estimation· Ms LamMCQ2
Percentage increase and decreaseConvert between percentages and multipliers so increase and decrease problems stay consistent.Percentage, Rate & Ratio· Ms LamMCQ3
Successive percentage changesCombine successive percentage changes by multiplying multipliers — never by adding the percentages.Percentage, Rate & Ratio· Ms LamMCQ4
Rate, ratio and direct proportionExpress ratios in simplest form, share quantities, and solve direct proportion problems with clear units.Percentage, Rate & Ratio· Ms LamMCQ5
Percentage applications: discount, profit and simple interestApply percentage tools to discount, profit/loss and simple interest — standard Secondary 2–3 applications.Percentage, Rate & Ratio· Ms LamMCQ6
Directed numbers with brackets (challenge)Mixed operations with multiple brackets — the step that trips many S2–S3 students in timed papers.Numbers & Estimation· Ms LamMCQ7
Reverse percentage problemsRecover the original value after a percentage change — classic exam reverse-percentage items.Percentage, Rate & Ratio· Ms LamMCQ8
Direct and inverse proportionDecide whether y varies directly or inversely with x, then solve with k — TSA-style classification plus calculation.Percentage, Rate & Ratio· Ms LamMCQ9
Percentage word problems (exam style)Weight change, profit and successive discounts with numbers in the spirit of S3 assessment items.Percentage, Rate & Ratio· Ms LamMCQ10
Absolute value of directed numbersRead |a| as distance from zero and simplify expressions with absolute values.Numbers & Estimation· Ms LamMCQ11
Comparing rational numbersCompare fractions and decimals using common denominators or decimal form.Numbers & Estimation· Ms LamMCQ12
Expressing one quantity as a percentage of anotherWrite A as a percentage of B using (A/B)×100%.Percentage, Rate & Ratio· Ms LamMCQ13
Rates in everyday contextsWork with speed, unit price and currency-style rates with units.Percentage, Rate & Ratio· Ms LamMCQ14
Collecting like terms with several variablesSort x, y and constant terms before combining coefficients.Algebraic Manipulation· Ms LamMCQ15
Factorising ax² + bx + c when a ≠ 1Split the middle term or use cross method for leading coefficient not 1.Algebraic Manipulation· Ms LamMCQ16
Identity or equation?Decide whether an equality is true for all values or only some values.Algebraic Manipulation· Ms LamMCQ17
Substitution with rearranged subjectsMake one variable the subject then substitute into the second equation.Equations & Inequalities· Ms LamMCQ18
Changing subject with powers and rootsUndo squares and cubes with roots, keeping context signs in mind.Equations & Inequalities· Ms LamMCQ19
Exam mix: simultaneous equations and inequalitiesSolve a pair of equations and an inequality back-to-back.Exam & Challenge· Ms LamMCQ