Grades K–2 · Computing
How does a stated rule sort shapes into groups?
A rule says which shapes belong in a group. Here the YES group means a shape has exactly three straight sides. A shape goes in NO when it does not match that rule.
In the diagramUse the same rule for every shapeYES rule: exactly three straight sidesAblueBCorangeDEFYES: matchesNO: does not matchA DB C E F2 match; 4 do not match.
The triangles match even when their colors differ. Circles and squares do not have three straight sides, so they belong in the other group. The rule applies to every card.
A different rule can make different groups. With a blue-label rule, the label matters instead of the number of sides. A shape has not changed just because its group changes. The stated rule explains where it belongs.
About this explanation
Starting knowledge: Recognize circles, triangles and squares, and count three straight sides with adult support.
Sources
- Common Core State Standards Initiative — Kindergarten: Classifying objects (K.MD.B.3)