GCSE's are nationally recognised qaulification, taken at secondary schools. The three main subjects for GCSE's are Maths, English, Science. Though RE, ICT, and PE is required to take (at my school anyway). And your chosen post year 9 courses. If you are on the alternative pathway you have 2 options of your desire, if you are in the core then you have 3, and on the extended you have 4. Its important to get atleast 5 A*-C grade if you want to get into to college and do your desired course. At college GCSE passes would help you to get on to A level course, BTEC'S,ACVE, and NVQ'S which are also nationally recogised. Level of qaulification start from 1. There are thousands of courses to choose from. The more GCSE's you pass the more choices you have after post 16. After college you may want to go on to higher education (university) or start training for work in any career you want to persuit.