MYP · Mathematics MYP Year 2
Algebra and Expressions
MYP Year 2 Mathematics — Algebra and Expressions
19 min readStandardCore strand — assessed through Criterion A (Knowing & Understanding) and Criterion B (Investigating Patterns) across the year
Algebra is arithmetic that hasn't decided on its numbers yet. Every mark lost in this topic comes down to one of three things: mixing up what's fixed with what changes, forgetting brackets when a negative number gets substituted, or writing an expression in the wrong order because you translated the words too literally. Get those three habits right and this whole topic becomes routine.
Overview — The Shape of Algebra
Algebra generalises arithmetic. Instead of working with one specific number, a letter stands in for a number that's unknown, changing, or simply not worth writing out every time — a taxi fare for any distance, a pattern rule for any figure number, a profit for any number of tickets sold.
- Writing expressions: turning a sentence into symbols, in the right order.
- Variables and constants: knowing which part of an expression can change and which can't.
- Substitution: plugging a specific number into a letter and simplifying correctly.
- Word problems: splitting a real situation into a fixed part and a per-unit part.
The shape of the chapter
Command terms this topic tests
| Command term | What it demands | AO | Mark-earning move |
|---|---|---|---|
| State | give a short answer with no justification required | AO1 | mark for the correct fact/expression alone — no working needed, but no partial credit for a vague answer either |
| Identify | pick out and name one specific feature | AO1 | must name the exact thing (e.g. 'the $1 fixed fee'), not describe the situation generally |
| Write | construct an expression or equation from given information | AO2 | mark for the correct symbolic form matching the context, including defining any variable used |
| Calculate | obtain a numerical answer with working shown | AO2 | method mark for correct substitution, separate mark for the correct final value |
| Explain | give a reason supported by evidence or context | AO3 | mark only given if the claim is linked to a specific calculation or context detail — 'because it's more realistic' scores nothing |
| Compare | state similarities and/or differences between two things | AO3 | no marks awarded if only one side of the comparison is addressed |
Key point
Every word-problem expression splits into two pieces: a fixed part (constant — never multiplied by the variable) and a per-unit part (coefficient × variable). Spotting that split correctly is worth more marks across this topic than any arithmetic step.
Overview