It contains a number of types of loans: 1- Simple method. 2- American method. 3- French method. 4- Linear method or german. 5- Geometric progression. 6- Arithmetic progression. 7- Prepayable interests. 8- Partial Lack deferred. 9- Lack Total deferred. 10- Fractional A. Constant. 11- Fractional French. 12- Usufruct and bare ownership. 13- Mortgage loan.