What Do You Notice? Number Skyline

Skills

Primary students (K-2): shapes, counting, repeated addition, area

Intermediate students (3-5): composite and prime numbers, array model of multiplication

Mathematical Background

These "buildings" represent prime and composite numbers. My goal was to create different arrays of each number - composite numbers would have more than one array and prime numbers would only have one array. To make the different numbers stand out, I used different color "buildings".

This activity does a nice job of visually reinforcing the area model of multiplication: L x W = A

Sample Student Responses

"Yellow is the biggest."

"All arrays that have the same outline color and box color have the same product."

"I see an unfinished bar graph."

"First 3 composite, last 2 prime, different array for each number, geometry."