Algebraic fractions follow the same rules as number fractions. Simplify by factorising the top and bottom and cancelling whole factors; add or subtract over a common denominator; multiply straight across, and divide by multiplying by the reciprocal. To solve an equation with fractions, multiply every term by the common denominator to clear them.
Factorise first, then cancel factors that appear on both the top and the bottom: . You can only cancel a whole bracket, never a single term inside a sum.
Adding and subtracting
Use the lowest common denominator and multiply each numerator by the factor its denominator was missing: . Put the subtracted numerator in brackets so the minus sign reaches all of it.
Multiplying and dividing
Multiply the tops and multiply the bottoms, cancelling common factors first. To divide, multiply by the reciprocal of the second fraction: .
Solving equations with fractions
Multiply every term, on both sides, by the common denominator. becomes , so . When the unknown is in a denominator the result is often a quadratic; check that no solution makes a denominator zero.
Key formulas
Expanding Learn it
Quadratic formula, On the formula sheet
On the formula sheet = printed on the formulae sheet in the 4MA1 Higher papers, so know where to find it. Learn it = not printed on the 4MA1 Higher formulae sheet, so learn it by heart. The whole 4MA1 formula sheet (free PDF) → · 4MA1 formulas to learn
Algebraic Fractions worked examples
Worked example 1: Simplifying an algebraic fraction
Simplify .
Solution
Factorise the top: .
Factorise the bottom: .
Cancel : .
Answer:
4 steps
Tip: Only cancel whole factors, never single terms.
Worked example 2: Adding algebraic fractions
Write as a single fraction.
Solution
Common denominator .
.
.
Answer:
4 steps
Tip: Multiply each numerator by the missing factor.
Worked example 3: Equation with algebraic fractions
Solve .
Solution
Multiply every term by : .
, so .
, giving or .
Answer: or
Answer: or
4 steps · 1 to fill in
Tip: Check neither answer makes a denominator zero.
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Algebraic Fractions exam-style questions
Try each question before you open the answer (one has its full worked solution open). The mark schemes use Edexcel-style marks: M for method, A for accuracy (after the method mark), B for an independent result.
Question 1 · easy · 3 marks
Solve .
Show the answer and mark scheme
M1 multiplies all terms by 15 (or common denominator)
M1 5(x + 4) − 3(x − 2) = 30 with correct signs
A1 x = 2
Answer:
Question 2 · medium · 3 marks
Solve .
Full worked solution Free, no sign-in
M1 5(x − 2) = 3(x + 1)
M1 5x − 10 = 3x + 3 (collects terms)
A1 x = 6.5 oe
Answer:
Every question here has a full worked solution.See them all →
Question 3 · medium · 3 marks
Solve .
Show the answer and mark scheme
M1 common denominator 2x, e.g. 8/(2x) + 3/(2x)
M1 11/(2x) = 11/2 or 22 = 11x oe
A1 x = 1
Answer:
Question 4 · hard · 4 marks
Solve . Give your solutions correct to 3 significant figures.
Show the answer and mark scheme
M1 3(x − 1) + 2(x + 2) = (x + 2)(x − 1)
M1 rearranges to x² − 4x − 3 = 0
M1 correct substitution into quadratic formula or completing the square, (x − 2)² = 7
A1 x = 4.65, x = −0.646 (accept 4.645…, −0.6457…)
Answer:
Question 5 · hard · 3 marks
Solve .
Show the answer and mark scheme
M1 x(x + 1) − 2(x − 3) = (x − 3)(x + 1)
M1 expands and cancels x² correctly, e.g. −x + 6 = −2x − 3
A1 x = −9
Answer:
Question 6 · hard · 3 marks
Solve .
Show the answer and mark scheme
M1 (x − 2)(x + 3) = 6
M1 x² + x − 12 = 0 and factorises (x + 4)(x − 3)
A1 x = 3, x = −4
Answer:
Question 7 · very hard · 4 marks
Solve .
Show the answer and mark scheme
M1 2[2(x + 2) − (x − 1)] = (x − 1)(x + 2) oe
M1 x² − x − 12 = 0 oe
M1 (x − 4)(x + 3) = 0 or correct formula
A1 x = 4, x = −3
Answer:
Question 8 · very hard · 5 marks
(a) Show that the equation can be written as . (3) (b) Hence solve , giving your solutions correct to 3 significant figures. (2)
Show the answer and mark scheme
M1 (a) x(x + 1) + 3(2x − 3) = 2x(2x − 3)
M1 x² + 7x − 9 = 4x² − 6x
A1 3x² − 13x + 9 = 0 (cso)
M1 (b) x = (13 ± √(169 − 108))/6 = (13 ± √61)/6
A1 x = 3.47, x = 0.865 (accept 3.468…, 0.8649…)
Answer:
Common algebraic fractions mistakes
Cancelling terms, not factors. In nothing cancels: the s are terms in a sum, not factors.
Multiplying only the fractions. When you clear fractions, multiply every term on both sides by the common denominator, including terms that are not fractions.
A minus sign that only reaches the first term. In the top is : keep the second numerator in brackets so the minus reaches every term.
Keeping a solution that breaks the equation. Check every solution in the original equation. A value that makes any denominator zero must be rejected.
How do I add algebraic fractions with different denominators?
Find the lowest common denominator (often the two denominators multiplied together), rewrite each fraction over it by multiplying its numerator by the missing factor, then add the numerators and simplify.
Why do some algebraic fraction equations turn into quadratics?
When the unknown is in a denominator, multiplying through by the denominators multiplies x by x, so an x² term appears. Rearrange to = 0 and solve by factorising or with the quadratic formula, which is on the 4MA1 Higher formulae sheet.
Can I use a calculator for algebraic fractions in 4MA1?
Yes. A calculator may be used in all four 4MA1 papers, so both Higher papers (1H and 2H) allow one. Most marks are for the method you write down, so show your working.
How long are the 4MA1 Higher papers?
Papers 1H and 2H are 2 hours each and 100 marks each, worth 50% each. Each tier has its own formulae sheet in the exam.
Every question and worked example here is original, written for IGCSE Math Revision rather than copied from Pearson papers, and every result was re-solved independently before publishing.
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