Comparing an old french mathematics book for grade 9 and a new one, one obvious difference is the ordering of the chapters. In the old book, all the algebra chapters are grouped together then all the geometry chapters so the teacher either should finish all the arithmetics and algebra before moving to geometry then to calculus or the school should have separate weekly periods for algebra and geometry. The new book mixes algebra and geometry chapters.
Is it better to finish algebra chapters before geometry or to mix them? I prefer the first one, I don't like to have geometry chapters between the polynomial chapter and the rational fractions for example or to have algebra chapters between similar triangles and trigonometry.