Each school curriculum subject is divided into teaching units, with each unit covering a defined portion of the subject capable of study as one unit within a maximum period of eighty-three (83) days i.e. in one course. Experts supervise each study subject in order to draw and define (the portion of) the subject to be studied in each term and each school stage. Likewise, they supervise dividing the subject into units corresponding to student ability and age. Subject units graduate sequentially until the entire subject is covered in the three school stages whether this sequence is from the easier to the more complicated as in Mathematics and Empirical sciences, or from comprehensive to details and branches like as in the subjects of the Prophetic Seerah and Islamic History. In scientific subjects like Mathematics, these units commence with the system of counting and simple arithmetic like addition and subtraction, then graduating to multiplication and division; then fractions and their functions, followed by algebra and equations. Then, in advanced stages, the student studies the principles of differential equations and Integral Calculus, Higher Mathematics and so on until the entire adopted Mathematics curriculum is covered in the school stages.

This requires the curriculum designer for specific teaching units to ensure that the subject conforms to student age, and to divide the subject intended for study in all stages into a maximum of 36 units, each unit in a book bearing the number of the course it will be studied in. The number of teaching units could be less than 36 for the subjects taught in later term e.g. physics. For instance, chemistry in the scientific branch is composed of 12 units; the students may commence the first unit in the 25th term and move onwards until the 36th term of the scientific branch of the school stage, whereas the general knowledge subject which is composed of 12 units, can commence in the 13th term and end in the 24th term.

The book bears the unit number as well as the course number to be studied in. So in the 25th term, for instance, the student studies Mathematics unit 25/25, Principles (qawa’id) unit 13/25, General Knowledge 12/25, Eloquence (Balagha) unit 6/25 etc.