What Do You Notice? Fractions on the Geoboard

Skills

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

Intermediate students (3-5): congruency, area, fractions, equivalent fractions

Mathematical Background

This is similar to the Squares and More Squares poster. Like that one, this was designed around fractions but at a higher level. The dots for each square represent the dots on a regular geoboard. Each square is made up of 5 by 5 dots. If lines were drawn connecting each of the dots, the larger square would show 16 small squares (4 x 4 small squares). Each of these small squares represents one square unit.

I divided each of the large squares into fourths. The third and fifth squares on the poster are the easiest representations of fourths. It is also easy to see equivalent fractions such as 1/2 = 2/4.

Upper elementary students can figure out the area of the sections by counting the square units. Just like in the Squares and More Squares poster, I deliberately made different shapes with the same area because sometime students will think that because the shape is different, the area must be different, as well.

Some students may notice congruency. For example, in the first square, two of the sections are identical (congruent) even though the orientations are different.

Sample Student Responses

"Each has 25 dots."

"They are all 4 straight lines on the outside."

"They all have four shapes inside of them."

"It's a four by four and inside there are squares."