Number Cross ®
Number Cross ® was created in 1989 and formally introduced at the 11th National Educational Computing Conference June 25, 1990. The concept was simple, a crossword type puzzle that uses numbers. The difference was that Number Cross ® uses random numbers to create an almost unlimited variety of puzzles. With four levels, a student could move from simple to complex. At level four, some problems in division and multiplication required a calculator to solve.
The product introduced three new concepts in education:
1. A learning theory called PAL (Positive Answer Learning).
2. The program was designed as a crossover product for children and adults.
3. The word crossfooting was created to show number relationships.
The program ended with the marketing phrase "Math is the Common Sense of Life SM".