Number Operations and Applications
MYP Mathematics Year 3 — Number strand: Number Operations and Applications
This chapter is less about learning new arithmetic and more about deciding which arithmetic to use, then trusting your number sense enough to sanity-check the answer. Every question here hides its operation inside ordinary words — each, total, net, per, split among — and marks are lost not because students can't multiply or divide, but because they picked the wrong operation or forgot to answer the actual question being asked (afford it? meet the target? support the claim?).
Overview — How This Chapter Fits Together
Number Operations and Applications sits on top of everything you already know — the four operations, fractions, rounding — and asks you to apply it inside a context: a shop, a budget, a recipe, a fundraiser. The skill being tested is translation: turning a sentence into a number sentence, then turning the numerical answer back into a real-world statement (can she afford it? did the shop hit its target?).
- Three moves repeat in almost every question: (1) identify the operation from the wording, (2) calculate carefully with correct units, (3) compare the result back to whatever the question actually asked about (a budget, a claim, a target).
- Models and 'real life' questions (bake sale profit, whole-dollar pricing) always have a hidden assumption — spotting what the model ignores is usually worth its own mark.
- Mixed numbers and improper fractions are the same values wearing different outfits — the operation you're about to do decides which outfit is useful.
The shape of the chapter
Command terms that drive the marks in this topic
| Command term | What it demands | AO | Mark-earning move |
|---|---|---|---|
| Calculate | Obtain a numerical answer, showing the working that leads to it. | Knowing & Understanding | A correct final number with zero working can still lose the method mark if it happens to be wrong — always write the number sentence first. |
| State | Give a short, direct answer with no justification required. | Knowing & Understanding | Writing a full explanation here wastes time for zero extra marks — a 1-mark 'state' question wants one line. |
| Explain | Give reasons, referencing the actual numbers or context given. | Applying & Reasoning | 'It could be wrong' with no numbers scores 0 — must name the specific effect (e.g. the error multiplies across every unit bought). |
| Analyse | Break the situation down and reach a justified verdict. | Applying & Reasoning | Must end in a clear yes/no or met/not-met statement backed by the calculated figures — the calculation alone, without the verdict sentence, typically only earns half the marks. |
| Apply | Use a given rule or model exactly as stated, in a new situation. | Applying & Reasoning | Marks are for using the model's own formula correctly — substituting your own shortcut instead of the given rule loses marks even if your shortcut also works. |
Key point
Overview