Form IV, form V, lower VI, and upper VI are the continuation and are a part of the secondary school, equivalent to a four-year high school in the American system. The third formers choose their IGCSE subjects towards the end of the year, and concentrate on their options over the next two years, before becoming IGCSE candidates at the end of Form V (except for advanced mathematians, who take the extended IGCSE Mathematics examinations at the end of Form IV, before taking the additional mathematics papers at the end of Form V). Students are expected to sit eight to ten IGCSEs, and must pass five in order to pursue the IB at the school.