Your device is currently offline. You can view downloaded files in My Downloads.

Lesson Plan

1. Partition shapes into halves (C)

teaches Common Core State Standards 1.G.4
teaches Common Core State Standards CCSS.Math.Content.1.G.A.3
teaches Common Core State Standards CCSS.Math.Practice.MP3
teaches Common Core State Standards MAFS.1.G.1.3
Quick assign

You have saved this lesson!

Here's where you can access your saved items.


Card of

or to view additional materials

You'll gain access to interventions, extensions, task implementation guides, and more for this lesson.

Lesson objective: Understand that shapes can be partitioned into two equal shares that we call halves, and that those two shares together equal one whole.

Students bring prior knowledge of modeling and composing shapes from Grade K, Unit 15, K.G.B.5. This prior knowledge is extended to introduce part-whole relationships of shapes as students partition shapes to demonstrate equal shares that we call halves. A conceptual challenge students may encounter is partitioning shapes unequally because they think that any two parts equal halves.

The concept is developed through work with basic shapes, like rectangles, which support an introduction into thinking about fractional parts of a whole (something students will need to know in future grades).

This work helps students deepen their understanding of equivalence because when a whole is partitioned into halves, the halves must be equal parts of the whole. Additional evidence of equivalence in these key concepts is that 2 halves equal 1 whole.

Students engage in Mathematical Practice 3 (construct viable arguments and critique the reasoning of others) as they help a student partition her rectangular room into equal shares.

Key vocabulary:

  • equal shares
  • halves/half
  • partition

Special materials needed:

  • pattern blocks
  • shape cut-outs
  • tangrams
Related content

Appears in

Finding equal shares of shapes

Provide feedback