IB MYP Math Criterion B — Investigating Patterns (8 Marks)
Criterion B is one of the most distinctive and challenging aspects of MYP Mathematics. It assesses your ability to discover, describe, and justify mathematical patterns — moving from observation to conjecture to general rule. It is worth 8 marks and is typically assessed through extended investigation tasks.
What Does Criterion B Assess?
Criterion B expects students to:
- Select and apply mathematical problem-solving techniques to investigate situations
- Describe patterns discovered as general rules in mathematical or verbal form
- Justify or verify the general rule they identify
- Extend the investigation to more complex cases
The key progression in Criterion B is: notice a pattern → state it as a conjecture → test it → justify it as a general rule. Students who only notice patterns without justifying them are capped at the lower mark bands.
MYP Criterion B Mark Descriptors
| Marks | Descriptor |
|---|---|
| 0 | The student does not reach a standard described by any of the descriptors below. |
| 1–2 | The student is able to apply, with teacher support, mathematical problem-solving techniques to discover simple patterns. |
| 3–4 | The student is able to select and apply mathematical problem-solving techniques to discover simple patterns; state predictions consistent with patterns. |
| 5–6 | The student is able to select and apply mathematical problem-solving techniques to discover complex patterns; describe them as general rules; verify the rule. |
| 7–8 | The student is able to select and apply mathematical problem-solving techniques to discover complex patterns; describe them as general rules consistent with findings; justify the general rule; extend the pattern to new cases. |
The Difference Between “Describe” and “Justify”
This is where many students lose marks. Describing a pattern means stating the rule in words or algebra: “As n increases by 1, the output doubles.” Justifying means explaining why this must be true — using algebra, logic, or a mathematical proof. A student who describes without justifying cannot exceed 5–6.
How to Score 7–8 on Criterion B
- Test enough cases to identify a reliable pattern (at least 5–6 examples)
- State your general rule using precise mathematical language or algebra
- Verify the rule for at least one additional case not used to find it
- Justify why the rule must hold — use algebra, diagrams, or mathematical reasoning
- Extend to a more complex version of the problem and show the rule still applies
Need Help With MYP Investigation Tasks?
Pattern investigation tasks are one of the areas where Mr. Ahmad’s tutoring makes the biggest difference. Many students know what a pattern is but struggle to articulate it mathematically and justify it with rigour. Get in touch to discuss MYP Math support in Dubai.
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