IB MYP 2 – Number Operation Properties (Criterion C)

IB MYP 2 Mathematics

Criterion C Task – Communicating: Number Operation Properties

You have 50 minutes to complete this task.
Show all your working and explain your thinking using correct mathematical language, symbols, and steps.
Use full sentences when giving definitions and justifications.

**Definitions:** In your own words, define the following properties and give one numerical example for each:
- Commutative Property (Addition and Multiplication)
- Associative Property (Addition and Multiplication)
- Distributive Property
- Identity Property (Addition and Multiplication)
- Inverse Property (Addition and Multiplication)
**Identifying Properties:** For each expression below, state the property being used and explain why.
- \( 6 + 9 = 9 + 6 \)
- \( (4 \times 5) \times 2 = 4 \times (5 \times 2) \)
- \( 3(4 + 7) = 3 \times 4 + 3 \times 7 \)
- \( 12 + 0 = 12 \)
- \( \frac{5}{6} \times \frac{6}{5} = 1 \)
**Explain the Error:** A student says that:

\( 5 + (3 + 2) = (5 + 3) \times 2 \)

Is this correct? Justify your answer using properties and show the correct evaluation of both sides.
**Create Your Own:** Write two of your own examples demonstrating:
- One correct use of the distributive property
- One incorrect use of any property (with explanation of the mistake)
For each example, write a full explanation of what property is shown and why it is applied correctly or incorrectly.

Level	Description
0	The student does not reach a standard described by any of the descriptors below.
1–2	Communicates mathematical ideas with limited clarity. Little use of appropriate terminology or representation.
3–4	Communicates mathematical ideas with some clarity. Some use of appropriate terminology and representation.
5–6	Communicates mathematical ideas clearly. Good use of appropriate terminology, representations, and logical steps.
7–8	Communicates mathematical ideas effectively and coherently, with consistent and accurate use of mathematical language and structure.