Module 4 - Mathematical Communication
TL;DR
Mathematical Communication is about how you lay out your work to make it easy to follow what you have done:
attempt all parts of the investigation;
label each part clearly.
The second criterion under mathematical communication is Communication.
This criteria is all about how easy it is to follow your work, and how clearly you have communicated your ideas.
It is always worth 3 further marks.
You have to have completed most of the sections in the investigation to get all 3 marks, and this includes a good attempt at Justify (normally at least 2 marks is required in Justify).
You also have to lay your work out in an easy to follow way, labelling the different sections.
I suggest you use titles (use bold when you type it up in the eAssessment) for the following sections:
Patterns
General Rule
Testing
Verifying
Justifying
By clearly labelling each part, you make it very easy for the examiner to know what you are doing at each stage, and this is required to get the full 3 marks.
If you were unable to do much of the justify step, you can still get 2 marks here by attempting all the other parts and labelling them clearly.