Math (even elementary) is fun!

The Introductory Algebra book was written on some notes for my daughter before she started 4th grade. It shall help anyone that needs a quick grasp of basic algebraic concepts. If you like the book, please spread the words. 4-9-2019
Add on 8-30-2020: In the past year (September 20219---August, 2020) I have taught local kids (6th graders) for 32 weeks, and some Chinese kids (online via CCtalk, from 4th grade to 6 grade. In Chinese, search 诸子数学) for 25 weeks. The rsults are very encouraging! My goal: starting from 4th to 6th grade, teach kids "introductory Algebra" (based on this book) first; After one year, teach kids "Geometry and Proof" (I have almost completed the writing of the book in Chinese. The English version shall be available by the end of this year (2020)); Then, I can teach them Trigonometric functions (I shall finish my writing of this book before my retirement or maybe even before we beat the Covid-19!). Yes, after three years, these kids are ready to take Calculus class! Sound exciting? If you want your kids to participate in this movement, start to read