We use the British terms for describing different years. In the US middle school is Grades 6 to 8, in Nigeria JS1 to JS3 however in the UK Years 7 to 9 and these are called Key Stage 3 or KS3 for short.
We follow the IMYC (International Middle Years Curriculum) which breaks the 3 years into 18 units of 6 weeks. Each unit starts with an entry point created by teachers where the theme is introduced and ends with an exit point created by groups of students pulling together all the knowledge, skills and understanding that they have gained during the unit.
The following are examples of the Big Ideas that we use
Balance (Year 7): Things are more stable when different elements are in the correct or best possible proportions
Resilience (Year 8): Success over time requires persistence
Challenge (Year 9): Facing up to, or overcoming, problems and barriers increases possibilities in our lives.