The first step of compulsory education in Britain is primary schooling for children between 5 and 11. The first two years are the years of infant school where the children are encouraged to read, to write in their own words, to understand and make use of numbers. Many children attend informal pre-school playgrounds organized by parents in private houses. Teachers and students in training work there. Kids are in the nursery classes while their parents work. At the age of 7 children go to the junior school where the teaching becomes more formal. They work in arithmetic, history, geography, nature study and music and English. The infant and junior schools may be regarded as two levels of primary education. Children begin their secondary education at about eleven years age. There are different types of secondary schools in England and Wales. The most popular are comprehensive schools. These are large state schools for boys and girls of all abilities aged 11-16 (or 18). Comprehensive schools were introduced in the 1960s with the aim to replace the system of dividing children between more academic (grammar) schools and less academic (modern) schools. There are some Grammar schools that still exist now. They teach more academic subjects than comprehensive schools.