Algebraic chemistry is based on numerical patterns observed in readily available data about ionisation potentials of atoms, and on a physical model that interpolates and extrapolates from that data to situations for which data is not readily available, such as ionisation potentials for atoms that are already ionised, or corresponding energy increments involved in adding, rather than subtracting, electrons. This Book presents an approach to chemistry that permits numerical evaluation of many chemical scenarios without use of much computation power. Everything here can be worked out with a hand calculator. The approach thus makes numerical analysis of scenarios in chemistry feasible for students, or up-coming researchers, or retirees, who work with minimal financial support.