Expanding and factorising
Expanding removes brackets; factorising puts them back. They are the same skill in reverse: every term in one bracket multiplies every term in the other, and factorising finds the brackets that would multiply out to give the expression.
≈ 30 minAlgebraic fractions and formulae
Algebraic fractions follow exactly the same rules as number fractions: factorise, cancel whole brackets, and use a common denominator to add. Changing the subject of a formula means undoing operations in reverse order, doing the same to both sides.
≈ 35 minLinear and simultaneous equations
An equation is a balance: whatever you do to one side, do to the other. Linear equations take a few balancing steps. Simultaneous equations have two unknowns, so you eliminate one of them first, then substitute back.
≈ 35 minQuadratic equations
Rearrange to . If it factorises, each bracket gives a solution. Otherwise use the quadratic formula, or complete the square, which also gives the turning point of the graph. In context, reject solutions that make no sense.
≈ 35 minInequalities and regions
Inequalities are solved almost like equations, with one trap: multiplying or dividing by a negative flips the sign. On a graph, an inequality in and is a region on one side of a line: solid line if included, dashed if not.
≈ 30 minSequences
A sequence follows a rule. Linear sequences go up by a constant difference, so their nth term is . Quadratic sequences have a constant second difference; geometric sequences multiply by the same number each time; Fibonacci-type sequences add the previous two terms.
≈ 30 minDirect and inverse proportion
Proportion links two quantities by one constant . Direct: , so grows with . Inverse: , so shrinks as grows. Write the equation, find from the given pair, then use it.
≈ 30 minFunctions
A function is a rule turning an input into an output. A composite means "do , then ". The inverse undoes : swap and and rearrange. Some inputs can't be used, such as values that make you divide by zero.
≈ 30 min