The letter i has many spelling variations, and the letter j is a common substitute. In electrical engineering, the imaginary unit is normally denoted by the letter j. For more information about the history of the i, see the SS History of the I. A common alternative for the letter i is a hyphen. This is the most widely used hyphen, but it is not the only one. In addition to hexes, i's also used in the plural.

Bryan Bunch's book Mathematical Fallacies and Paradoxes has been a popular choice for students. Henri Picciotto's Algebra: Themes, Tools, and Concepts was published by Cengage Learning. And, if you'd like a more advanced treatment of the subject, henri Picciotto'S book, Introduction to Algebra, is also a popular choice.