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#Algebra

7 articles about Algebra.

Learning maths · 7 min read

Why do we "flip and multiply" when dividing by fractions? Explaining the reasoning with diagrams

Children often ask: why do we flip the divisor and multiply when dividing by a fraction? This article uses diagrams and step-by-step demonstrations to explain the reasoning behind "dividing by a fraction is the same as multiplying by its reciprocal", and brings together common mistakes and practice methods. It is suitable for Primary 5 to Primary 6 students and parents to read together.

Learning maths · 6 min read

Quadratic Function Graphs: Steps to Find the Vertex, Axis of Symmetry and Intercepts from the Equation

Many students see a quadratic function and think only of memorising formulas. In fact, as long as you work through it step by step, finding the axis of symmetry, vertex and intercepts from the equation lets you draw the parabola reliably. This article uses S4 to S6 quadratic functions as examples, demonstrates the full steps, and explains common mistakes and revision methods.

Learning maths · Updated · 4 min read

Solving inequalities: when does the sign flip? Linear, compound "and"/"or" and quadratic inequalities, with examples

The most common mistakes with inequalities are forgetting to flip the sign after multiplying or dividing by a negative number, and mixing up "and" with "or". Following the Education Bureau curriculum documents, this guide covers junior secondary linear inequalities and the senior compound inequalities, quadratic inequalities and linear programming, with worked examples, which parts are non-foundation and where they appear in the HKDSE, plus ways to check and the key terms in Chinese and English.

Learning maths · Updated · 10 min read

How to find the equation of a straight line: point-slope, two-point, slope-intercept and general form, with examples

The equation of a straight line is a compulsory senior secondary maths topic, which the Education Bureau suggests teaching in the first term of Secondary 4. This guide follows the curriculum documents: the distance, mid-point, slope and point-of-division (section) formulas; finding a line from a point and a slope, two points or two intercepts; reading slope and intercepts from the general form; and where two lines meet, with ways to check your answer.

DSE revision · 11 min read

What is the difference between DSE M1 and M2? Understand the content, suitable students and further study uses before choosing subjects

Compare the curriculum content, suitable students and further study uses of DSE Mathematics Extended Part Module 1 (M1) and Module 2 (M2), explain how the two are handled in university admissions and sub-degree programmes, and remind candidates to rely on the requirements announced by institutions.