Algebra and Expressions
MYP Mathematics Framework — Number & Algebra strand (Year 3)
Algebra in Year 3 is really just arithmetic wearing a disguise — the letters stand for numbers you haven't pinned down yet, and every rule you already know (order of operations, how negatives behave, how multiplication distributes) still applies underneath. Almost every mark lost on this topic comes from one of three habits: losing track of a sign when rearranging, multiplying only part of a bracket, or forgetting that a letter can only carry one meaning at a time. Fix those three and most of this topic looks after itself.
Overview — The Shape of Algebra and Expressions
An algebraic expression is a collection of terms — numbers, letters, or both, multiplied or divided together and joined by or signs — with no equals sign in sight. That last part matters: an expression can be simplified, expanded, factorised or evaluated, but it can never be 'solved' the way an equation can, because there's nothing on the other side to solve for.
- Everything in this topic is built from four moves: simplify (collect like terms), expand (remove brackets using the distributive law), factorise (put brackets back in, in reverse), and substitute (swap letters for numbers).
- Word problems and pattern/sequence questions are just these four moves applied to a real context — the algebra doesn't change, only the story around it does.
- MYP examiners consistently test whether you can justify a simplification, not just perform it — several of the sample questions ask you to predict, compare, or explain your working, not merely calculate it.
The shape of the chapter
Command terms this topic actually uses
| Command term | What it demands | AO | Mark-earning move |
|---|---|---|---|
| Calculate | Obtain a numerical or algebraic answer with relevant working shown. | AO1 | No visible working means a wrong final line loses ALL the marks, not just the accuracy mark. |
| Identify | Pick out and name the specific feature asked for — no explanation needed. | AO1 | Naming the wrong feature (e.g. listing coefficients when asked for like terms) scores zero however good the later working is. |
| State | Give a short answer with no justification required. | AO1 | The answer must actually appear — it isn't awarded just because it's 'implied' by later steps. |
| Compare | Set two results side by side and comment on how they relate. | AO2 | Writing both answers without linking them ('they are equal because…') misses the comparison mark entirely. |
| Justify | Support a conclusion with a reason or evidence, not just a verdict. | AO2 | A bare 'yes' or 'correct' scores zero on a Justify question even when the verdict itself is right. |
| Explain | Give the reasoning behind why or how something works. | AO2 | Repeating the calculation instead of stating the underlying reason is the most common way this mark is lost. |
| Apply | Use an established rule or method in a new but similar situation. | AO1 | Re-deriving the rule from scratch instead of just applying it wastes time for no extra credit. |
| Show | Display every step of working, not only the final answer. | AO2 | Jumping straight to the simplified answer loses the specific 'method shown' marks even if that answer is correct. |
Key point
Overview