Is Number and Algebra assessed differently in IB Maths AA SL and HL?

SL and HL share the core work on standard form, sequences and series, financial applications, exponents, logarithms, simple proof, infinite geometric series, and the binomial theorem for natural-number powers. HL students must additionally study counting principles, extended binomial series, partial fractions, complex numbers, advanced proof, and systems of linear equations. Both levels can encounter Number and Algebra on Paper 1 and Paper 2. HL students may also need these ideas within the extended problem-solving structure of Paper 3. The difference is therefore both the amount of content and the depth with which algebraic reasoning is assessed.

Which Number and Algebra formulas must I memorise for the exam?

Students receive a clean copy of the official mathematics formula booklet in the examinations, so you should first learn what it contains and where each formula appears. However, access to a formula does not remove the need to understand its conditions and variables. For example, the infinite geometric-series formula is useful only when the common ratio satisfies |r| < 1. Basic algebraic identities, logarithm laws, proof structures, and routine manipulations should become fluent because repeatedly searching for them wastes time. Practise with the booklet used by your school so that selecting and adapting formulas becomes automatic.

How can I tell whether a sequence is arithmetic or geometric?

An arithmetic sequence has a constant difference between consecutive terms, while a geometric sequence has a constant ratio. Language involving a fixed amount added or removed usually points to an arithmetic model. Language involving a percentage change, repeated growth factor, compound interest, or depreciation usually points to a geometric model. If terms are provided, calculate consecutive differences and ratios rather than judging only from appearance. Real contexts may not follow either model perfectly, so use the model specified or supported by the data in the question.

Do I need to show working on calculator questions in Paper 2?

Yes, you should show enough mathematical setup to make your method clear even when technology performs the numerical calculation. Write the relevant equation, sequence formula, logarithmic model, or system before recording calculator output. A bare decimal answer may not demonstrate the reasoning needed for method marks, especially if the final value is wrong. Keep unrounded calculator values during intermediate steps and round only the final answer as instructed. If a graph is used to solve an equation, record the equation and relevant intersection or root rather than writing only the displayed coordinate.

What is the best way to prepare for proof questions in Maths AA?

Begin by identifying the type of statement and the proof method it suggests. Divisibility and parity results often use algebraic definitions, while a false universal claim can be rejected with one valid counterexample. At HL, induction requires an initial case, an explicit hypothesis, a valid k-to-k+1 step, and a concluding statement. Contradiction begins by assuming the negation of what must be proved and deriving an impossibility. After learning these structures, practise writing complete proofs without relying on remembered wording that is disconnected from the algebra.

How should I use past paper video solutions effectively?

Attempt the question under realistic conditions before opening the video, including the correct calculator rule. Mark the point where you became stuck and preserve your original working so that you can diagnose the actual problem. While watching, compare the chosen method, intermediate notation, use of formulas, and final answer form with your response. Pause before each major step and predict what should happen next, because active prediction produces more learning than passive viewing. Finally, redo the question without support and complete a similar question a few days later to check that the method has transferred.

IB Maths AA Number & Algebra Explained for Exams

Q: How can I tell whether a sequence is arithmetic or geometric?

An arithmetic sequence has a constant difference between consecutive terms, while a geometric sequence has a constant ratio. Language involving a fixed amount added or removed usually points to an arithmetic model. Language involving a percentage change, repeated growth factor, compound interest, or depreciation usually points to a geometric model. If terms are provided, calculate consecutive differences and ratios rather than judging only from appearance. Real contexts may not follow either model perfectly, so use the model specified or supported by the data in the question.

Q: Do I need to show working on calculator questions in Paper 2?

Yes, you should show enough mathematical setup to make your method clear even when technology performs the numerical calculation. Write the relevant equation, sequence formula, logarithmic model, or system before recording calculator output. A bare decimal answer may not demonstrate the reasoning needed for method marks, especially if the final value is wrong. Keep unrounded calculator values during intermediate steps and round only the final answer as instructed. If a graph is used to solve an equation, record the equation and relevant intersection or root rather than writing only the displayed coordinate.

Q: What is the best way to prepare for proof questions in Maths AA?

Begin by identifying the type of statement and the proof method it suggests. Divisibility and parity results often use algebraic definitions, while a false universal claim can be rejected with one valid counterexample. At HL, induction requires an initial case, an explicit hypothesis, a valid k-to-k+1 step, and a concluding statement. Contradiction begins by assuming the negation of what must be proved and deriving an impossibility. After learning these structures, practise writing complete proofs without relying on remembered wording that is disconnected from the algebra.

Q: How should I use past paper video solutions effectively?

Attempt the question under realistic conditions before opening the video, including the correct calculator rule. Mark the point where you became stuck and preserve your original working so that you can diagnose the actual problem. While watching, compare the chosen method, intermediate notation, use of formulas, and final answer form with your response. Pause before each major step and predict what should happen next, because active prediction produces more learning than passive viewing. Finally, redo the question without support and complete a similar question a few days later to check that the method has transferred.

Emma C.

•Last updated: 5 Aug 2026•14 min read

IB Maths AA Number & Algebra is built around a manageable set of testable ideas: numerical representation, sequences and series, exponents and logarithms, proof, and binomial expansion, followed at HL by counting, partial fractions, complex numbers, advanced proof, and linear systems. To score consistently, you must do more than recall formulas: you need to recognise the question type, select an efficient method, show mark-earning working, and present the answer in the requested form.

This exam-focused explanation covers what SL and HL students need to know, how IB questions are commonly phrased, and where avoidable marks are lost. After learning each method, use per-question IB Maths AA past paper video solutions to see how the theory becomes a complete written solution.

Where Number and Algebra Fits in IB Maths AA

Number and algebra is Topic 1 of the official Mathematics: Analysis and Approaches syllabus. The IB recommends approximately 19 teaching hours at SL and 39 hours at HL, although these are teaching recommendations rather than limits on how much the topic can appear in an examination.

All five syllabus topics are compulsory. Number and algebra can also be combined with functions, calculus, probability, or financial modelling, especially in extended-response questions and HL Paper 3. The official IB Maths AA subject brief gives the current course structure and assessment weighting.

Assessment	SL format	HL format	Technology
Paper 1	90 minutes, 40%	120 minutes, 30%	No calculator
Paper 2	90 minutes, 40%	120 minutes, 30%	Technology required
Paper 3	Not taken	60 minutes, 20%	Technology required
Exploration	20%	20%	As appropriate

Paper 1 particularly rewards fluent algebra because calculations must be completed without a calculator. Paper 2 may require technology, but calculator output still needs mathematical setup and interpretation. The official guide also states that students receive a clean formula booklet, so learning to locate and apply formulas is more useful than memorising every expression without context.

The Core SL Ideas Examiners Test

The RevisionDojo Number and Algebra notes follow the syllabus sections in order, while the summary below groups them by the decisions students must make in exams.

Standard Form and Numerical Accuracy

You must operate with numbers written as a × 10^k, where 1 ≤ a < 10 and k is an integer. Questions may ask you to express a result in standard form, compare extremely large quantities, or preserve appropriate significant figures.

For example:

(6 × 10^7)(4 × 10^-3) = 24 × 10^4 = 2.4 × 10^5.

The first product is numerically correct but is not yet in standard form because the leading value is 24. If a question requests an exact answer, do not replace surds, fractions, logarithms, or multiples of π with decimals.

Arithmetic and Geometric Sequences

For an arithmetic sequence, the difference between consecutive terms is constant:

nth term: u_n = u_1 + (n - 1)d
sum: S_n = n/2[2u_1 + (n - 1)d]

For a geometric sequence, consecutive terms have a constant ratio:

nth term: u_n = u_1r^(n - 1)
finite sum: S_n = u_1(1 - r^n)/(1 - r), for r ≠ 1
infinite sum: S_∞ = u_1/(1 - r), valid only when |r| < 1

The central exam skill is identifying the model. A fixed increase, such as adding $500 each year, suggests arithmetic behaviour; a percentage increase, compound interest, depreciation, or repeated multiplication suggests geometric behaviour.

Questions often say “find the least value of n” or “determine the first year in which”. Form an inequality rather than an equation, solve it using logarithms or technology as appropriate, and check the neighbouring integer because n normally represents a whole number.

Exponents and Logarithms

You should be able to simplify rational powers, apply logarithm laws, change base, and solve exponential equations. The essential laws include:

log_a(xy) = log_a x + log_a y
log_a(x/y) = log_a x - log_a y
log_a(x^p) = p log_a x
a^x = b if and only if x = log_a b

A common trap is writing log(x + y) = log x + log y, which is false. Logarithm laws apply to products, quotients, and powers, not to sums or differences.

For 3^(2x - 1) = 7, taking logarithms gives (2x - 1)ln 3 = ln 7, so x = 1/2[1 + ln 7/ln 3]. This exact form is appropriate unless the question requests a decimal approximation. Targeted practice is available in the laws of exponents and logarithms topic.

Simple Deductive Proof

SL proof focuses on valid algebraic or numerical deduction. You may be asked to prove a divisibility result, establish an identity, or disprove a universal statement with a counterexample.

For example, to prove that the sum of two odd integers is even, write the integers as 2m + 1 and 2n + 1. Their sum is 2m + 2n + 2 = 2(m + n + 1), which is divisible by 2. Testing a few odd numbers suggests the result, but the algebra proves it for all integers m and n.

The Binomial Theorem

At SL, you expand (a + b)^n for a non-negative integer n using binomial coefficients. The general term is

T_(r+1) = C(n,r)a^(n-r)b^r.

If asked for the coefficient of x^5, do not expand everything automatically. Write the general term, determine which value of r produces x^5, and then calculate that coefficient. Carefully distinguish the term containing x^5, which includes x^5, from its coefficient, which does not.

Additional Number and Algebra at HL

HL students study all SL content plus the additional higher level, or AHL, material. The IB Maths AA Number and Algebra hub separates the relevant SL and HL resources.

Counting, Extended Binomial Expansions and Partial Fractions

Counting questions test permutations, combinations, and restrictions. Order matters in a permutation but not in a combination, so “arrange” usually signals a different calculation from “select.” Restrictions such as objects staying together or particular choices being excluded should be handled before entering values into a formula.

HL extends binomial expansion to fractional and negative powers. These are generally series rather than finite expansions, and validity depends on the stated range, commonly |x| < 1 after the expression has been put into an appropriate form.

Partial fractions reverse the process of combining rational expressions. Before decomposing, check that the numerator’s degree is lower than the denominator’s; if not, perform polynomial division first. Examiners frequently connect partial fractions to integration, so inaccurate algebra here can affect marks in a later calculus part.

Complex Numbers

You need to move between:

Cartesian form: z = a + bi
modulus-argument form: z = r(cos θ + i sin θ)
Euler form: z = re^(iθ)

In Cartesian form, addition and subtraction are direct. Polar or Euler form is usually more efficient for multiplication, division, powers, and roots. HL questions may also test conjugates, loci on an Argand diagram, complex conjugate roots of real polynomials, De Moivre’s theorem, and the full set of nth roots.

When finding roots, include all arguments generated by adding 2kπ before dividing by n. Listing only the principal root is one of the most costly complex-number mistakes.

Advanced Proof and Linear Systems

HL proof includes mathematical induction, contradiction, and counterexample. A complete induction proof should establish the initial case, state the inductive hypothesis, prove the result for k + 1 using that hypothesis, and give a conclusion covering the required integers.

Linear-system questions can produce one solution, no solution, or infinitely many solutions. During elimination, a row such as 0 = 5 signals inconsistency and therefore no solution. A row of zeros may indicate infinitely many solutions, provided the remaining equations are consistent and leave at least one free variable.

How IB Questions Turn These Ideas into Marks

Pay attention to the command and the requested answer form:

Wording	What your response must show
Find or determine	A valid method followed by the requested value
Show that	Logical working that reaches the supplied result without assuming it
Hence	Use the preceding result rather than restarting unnecessarily
Prove	A general argument, not several numerical examples
Write in the form	Algebraic rearrangement into exactly that representation
Give an exact answer	Fractions, surds, π, e, or logarithms rather than rounded decimals

Method marks matter. Write the sequence model before substituting, show the logarithmic equation before using a calculator, and identify the relevant binomial term before stating its coefficient. The official specimen papers and markschemes illustrate the expected level of working and presentation.

Common Mistakes and a Better Revision Method

The most frequent problems are procedural rather than conceptual:

using the infinite geometric sum when |r| ≥ 1
confusing a term number with the sum of the first n terms
rounding halfway through a calculation
applying logarithm laws to addition
expanding a binomial when only one term is required
giving examples instead of a general proof
omitting induction conclusions or complex roots
copying calculator output without mathematical setup

Revise in short feedback loops. Review one method, answer several questions without notes, mark the working rather than only the final answer, and record the reason for every lost mark. Use the Number and Algebra Questionbank for targeted practice and the Number and Algebra video lessons when a method needs rebuilding.

Once individual skills are secure, attempt mixed questions under Paper 1 or Paper 2 conditions. Then watch the per-question video solution and compare the setup, algebra, notation, and final form with your own response rather than passively watching from the beginning.

Conclusion

IB Maths AA Number & Algebra becomes manageable when you classify questions into a small number of recurring structures and practise presenting each method clearly. SL students should prioritise sequences, logarithms, proof, and binomial expansion; HL students must add counting, partial fractions, complex numbers, advanced proof, and linear systems.

RevisionDojo can support this sequence from understanding to performance: use Study Notes or Jojo AI to clarify a method, the Questionbank to practise it, and past paper video solutions to see how a complete answer earns marks. The most useful next step is to attempt a question independently before opening its worked video solution.