A Quick Clarification

I've realised that I've been using "Grade     " when referring to the classes I am teaching without explain what the conversion is with the British system.

Based on the average ages in each grade:
Grade 8 is the equivalent of Year 9;
Grade 9 is the equivalent of Year 10;
Grade 10 is the equivalent of Year 11;
Grade 11 is the equivalent of Year 12 and
Grade 12 is the equivalent of Year 13.

In Grade 12 they take what they call the Matric and is their pre-University qualification.

Hope this helps!