In addition to interactive sections, several videos have been inserted. They include simple visual interpretations of prime factorization, upside down division that features rules of divisibility, and the Sieve of Eratosthenes. The numbers 1-100 are grouped and the “Sieve” procedure is demonstrated in four separate videos. For those who like a challenge, a bonus spreadsheet grid has been included, for a limited time only.
Although not a prerequisite, previous books by this author provide an in-depth look at rectangle dimensions and factors, and include greater detail for development of those concepts. Inching Along (square units) and All Set (factors) build the foundation. About Prime (prime numbers), ends the trilogy, and shows a connection between rectangles and prime numbers.
The beauty of mathematics lies in an awareness of how so much of the number system is interrelated in some way, even at an elementary level. That understanding must be present before introducing abstract concepts in the system.