Illustration of Understands and applies number operations and properties in the ICLE's Rigor and Relevance Framework
Quadrant C

A four digit number (in base 10) aabb is a perfect square. Discuss ways of systematically finding this number.
("Novemberish" from

Quadrant D

Research the change of the ISBN system from the former 10-digit format to the new 13-digit format. Explain the reasons for the new system and determine the benefits and any problems that may occur. Also determine what types of entities are affected by this major change and how they are affected.
("Check that Digit" prepared by Doug Schmid on http://illuminations.nctm.org/LessonDetail.aspx?id=L693)
Quadrant A

Find the congruent value of 100 in mod 2, mod 7, and mod 12.

 Quadrant B

Many codes including bar codes and credit card numbers have a "check Qnumber" as the last digit of the code. This allows the companies to determine if account numbers are valid by combining numbers using an algorithm and checking to see if the result is divisible by a certain number or modulus. Determine if the following account numbers are valid using the given algorithm.
("Check that Digit" prepared by Doug Schmid on http://illuminations.nctm.org/LessonDetail.aspx?id=L693)