MYP Maths: Negative Numbers & Integers Explained (FAQs)

Integers are whole numbers — positive, negative and zero — with no fractional or decimal part, so -5, -1, 0, 4 and 100 are all integers. Negative numbers are simply integers less than zero. In MYP Maths this sits under the Number branch and underpins later work in algebra and coordinate geometry.

Most confusion comes from the double-negative rule — subtracting a negative feels backwards until you picture it on a number line. I've taught MYP Year 1 classes where half the room flips the sign on "−3 − (−5)" every time, until we walk through it as undoing a debt rather than a rule to memorise.

Adding a negative is the same as subtracting: 4 + (−3) = 4 − 3 = 1. Subtracting a negative is the same as adding: 4 − (−3) = 4 + 3 = 7. Picture a number line — moving right for positive, left for negative — and the sign rules stop feeling arbitrary.

The rule is simple once it's automatic: same signs give a positive answer, different signs give a negative one. So (−4) × (−3) = 12, but (−4) × 3 = −12. Division follows the identical sign rule, so −15 ÷ 3 = −5 and −15 ÷ (−3) = 5.

MYP Maths leans hard on contexts students can picture: temperature below zero, elevation below sea level, bank overdrafts and game scores. This ties directly into MYP global contexts such as Globalisation and sustainability, and it matters for Criterion D — Applying mathematics in real-life contexts — not just abstract number work.

There's no single 'integers test' — negative numbers get assessed through the four MYP Mathematics criteria in whichever unit uses them, most often Criterion A (Knowing and understanding) and Criterion D (Applying mathematics in real-life contexts). According to the IB's MYP: Mathematics guide, each criterion is marked out of 8, giving a total out of 32 that converts to the final 1-7 subject grade.

Integer and negative-number skills mostly sit under Criterion A – Knowing and understanding, since it tests whether you can select and apply the correct rules and reach accurate answers. But when a task asks you to interpret a real situation — a temperature drop, an overdraft — Criterion D – Applying mathematics in real-life contexts comes into play too.

The biggest mistake I mark down for is a sign error carried through multi-step working — the method is right, but a dropped negative sign on line two poisons every line after it. Examiners applying MYP criteria still credit correct method where they can, but Criterion A demands an accurate, not just approximately correct, final answer.

Drill the sign rules until they're automatic, then move straight to multi-step problems mixing addition, subtraction, multiplication and division of integers in one question — that's what separates a level 5-6 answer from a level 7-8 one under Criterion A. Practising single-operation questions in isolation only gets you so far.

Short, frequent practice beats one long session — ten mixed integer questions most days embeds the sign rules far better than an hour once a week. Mixing operations (add, subtract, multiply, divide) in the same set forces your child to identify which rule applies, which is exactly what MYP assessment expects.

First exams for the current DP Mathematics: Analysis and Approaches and Applications and Interpretation guides were held in 2021, and the algebra skills tested there — negative gradients, negative indices, inequalities — trace straight back to the integer work done in MYP Years 1 to 3.

MYP Year 1 introduces integers and basic sign rules through simple one-step problems; Year 2 moves to multi-step calculations mixing all four operations; Year 3 embeds negative numbers inside algebra, coordinates and ratio problems rather than teaching them as a stand-alone topic. The sign rules themselves never change.

Many students arrive at MYP having learned negative numbers by rote rule — 'two negatives make a positive' — without ever seeing why. MYP Mathematics pushes concept-based learning, so your child will be asked to explain reasoning and justify answers, not just compute them, which is assessed directly under Criterion C, Communicating.

Look for material organised by MYP criterion rather than generic worksheets, so your child's practice actually matches how the topic is graded. Short-answer worksheets with full worked solutions are more useful than random online quizzes, because they show the working an examiner expects to see for Criterion A and C marks.