Australians start going to school at the age of six. The following six years they are in primary school, which is run by the state or in a private school which is almost always run by a church. The schoolday is from am to pm. After primary school there is secondary school which takes another six years. School is mandatory until the age of fifteen. Most children leave school at this age. For students who live far outside a city, there is an institution called School on the Air. This school is conducted over the two-way radios.