I am a chemical engineer with a MS in Food Technology and Economics, and a MENSA member. I am the author of the book "Investing in Stocks and Bonds: The Early Retirement Project" (2024):I am also the author of the book "Mental Math: How to perform math calculations in your mind".I am also the author of 2 other mathematics books ("Arithmetic calculations without a calculator" and "Word Problems") and perform almost all the calculations in my mind, without a calculator, making it easier to make immediate inve ...