MYP Maths: Solving Simple Equations — FAQs for Students and Parents

Solving a simple equation means finding the value of the unknown letter that makes both sides equal — working out that x = 7 in x + 3 = 10, for instance. In MYP 1-3 this sits mainly under Criterion A: Knowing and Understanding, and it builds the algebraic reasoning that IB DP Maths AA and AI both assume you already have.

An expression is a string of numbers, letters and operations with no equals sign — 3x + 2, for example — and it can only be simplified, never solved. An equation always has an equals sign, like 3x + 2 = 11, stating that two things are equal, which is exactly what allows you to solve for the unknown.

Inverse operations undo each other — addition undoes subtraction, multiplication undoes division — and solving any equation really is just applying the correct inverse operation to both sides until the letter stands alone. Get the order wrong and you'll usually end up with the wrong sign or an unnecessary fraction.

You isolate the unknown by undoing operations in reverse order — addition and subtraction first, then multiplication and division — applying the same step to both sides every time. Take 4x + 5 = 17: subtract 5 from both sides to get 4x = 12, then divide by 4 to get x = 3.

Collect all the letter terms onto one side first, then all the number terms onto the other, before solving as normal. For 5x − 3 = 2x + 9: subtract 2x from both sides to get 3x − 3 = 9, add 3 to get 3x = 12, then divide to get x = 4.

Substitute your answer back into the original equation and confirm both sides give the same value — if 4x + 5 = 17 and you found x = 3, then 4(3) + 5 = 17 checks out. Examiners call this verifying, and it catches sign errors before they cost you Criterion A marks.

The three mistakes I see most often, marking mock papers, are forgetting to apply an operation to both sides, mishandling negative signs when moving terms across the equals sign, and stopping before checking whether the answer actually works. Each one is fixable with a habit of writing out every step rather than solving in your head.

Solving equations is assessed mainly under Criterion A: Knowing and Understanding, where students select and apply mathematical practices to solve problems in familiar and unfamiliar situations. It can also appear in Criterion C (Communicating) when reasoning must be shown clearly, and Criterion D when an equation models a real-life context.

Most MYP unit planners introduce one- and two-step equations with positive integers in MYP 1, negative numbers and simple fractional coefficients in MYP 2, and equations with brackets or the variable on both sides by MYP 3. Individual schools sequence this slightly differently, but that progression is the general pattern across the programme.

In MYP 1-3, equations show up in Criterion D tasks where you model something real — how many weeks it takes to save for trainers, or how a phone plan's cost changes with data used — and then solve an equation to answer the actual question, not an abstract one. That's the point of the real-life contexts strand.

Every DP Mathematics: Analysis and Approaches or Applications and Interpretation course assumes fluent equation-solving from the first unit — quadratics, simultaneous equations and later calculus all rest on the same inverse-operation skills taught in MYP 1-3. According to the IB, first exams for the current Maths AA and AI guides were held in 2021, and both build directly on this MYP algebra base.

Not really "harder" — MYP Mathematics covers broadly similar content to most national curricula for ages 11–14, but it assesses understanding differently, through four separate criteria rather than one combined mark scheme, with real-life application (Criterion D) weighted equally alongside procedural skill. Parents usually find the criteria structure unfamiliar rather than the actual maths itself.

Consistent short practice beats occasional long sessions — 15 minutes of mixed equation problems three or four times a week embeds the inverse-operation habit better than one hour once a week. Structured topical worksheets that isolate one skill at a time (one-step, then two-step, then variable-on-both-sides) work far better than random mixed-difficulty homework sheets.

The fastest confidence gain comes from doing the same equation type ten times in a row until it's automatic, then mixing types together — not from jumping straight into a mixed worksheet on day one. Past MYP-style questions with full worked solutions, plus short topic notes covering each equation type separately, let you see exactly where your method breaks down.