Forget the jargon. Forget the anxiety. Just remember the math.

In this age of cheap calculators and powerful spreadsheets, who needs to know math? The answer is: everyone. Math is all around us. We confront it shopping in the supermarket, paying our bills, checking the sports stats, and working at our jobs. It is also one of the most fascinating-and useful-subjects. Mastering math can make a difference in your career, your studies, and your daily life.

If you are among the millions of people who would love to understand math but are turned away by fear of its...