Mathematical Finance belong to the Finance Engineering but employing more mathematics, following the Financial Laws of Pacioli's IFRS (International Finance Reporting Standards) and GAAP (Generally Accepted Accounting Principles). It is totally is different and very contrast (opposite) to the commonly known Financial Mathematics which are branches of Mathematic (mostly Investment Algebra), enriching the Investment from outside, such as TVM (Time Value of Money) and BEP (Break Even Point), etc., which never touching Core Finance and nor Accounting Rules important to Firm's Health Firm's health is very important, when properly controlled it could prevent bankruptcy and avoid innocent people from being poor. It is the greatest problem in economy, much greater than any cases ever solved by Economic Nobel Laureates, so far. The nicest thing about it, is that only requires simple Junior Highschool Algebra. We just need to be consistent with its less number treatment of constellations. Its saddest part is that many professors and doctors are no longer able to understand Junior Highschool Algebra, and hiding in Accounting jargons. Please go back to its Introduction for glossary, at anywhere inside the book, so then we can still understand what are those mean with simple Algebraic Rule there. We try to avoid some sentences multiplied, added, eliminated divided, rooted or powered by another sentences, that make many traditional finance book successful (delivering few simple things, seen as difficult and scary), but less useful and seldom be accurate.