Wednesday, April 4, 2012

Prime and Composite Numbers with Color Tiles

One of my objectives for 5th grade math is differentiating between prime and composite numbers by using models.  Color tiles work well for this objective.  I reviewed arrays from 3rd grade with them while discussing the vocabulary prime, composite, factor, multiple, and array.

To begin with, I read on Math Goodies a neat way to explain it linking it to perimeter and area. The way I am going to explain it to my students is building a garden If I said I wanted a garden with 5 sq. ft. the dimensions can only be 1 ft. + 1 ft.  + 5 ft.  + 5 ft. , and the area would be 5 sq. ft. This is the ONLY way to build the garden to those specifications.
Stress that this being the only way makes it prime!!
If you can build the garden MORE THAN ONE way, it is a composite number.
More than one way to build make is composite!!