To show those teaching upper-grade math and high school first year math how their students can perform arithmetic based on these identities. Prepare packets of pre-cut squares and rectangles, one for each student.
All measurements start from the lower-left hand corner of the large square.
In addition, prepare a set of the four cut rectangles very much enlarged. They must be on heavier still cardboard and backed with magnetic strip material to adhere to typical metallic base chalkboards. The teacher's uncut square should be pre-folded along the heavy vertical and horizontal lines. Immediately have students remove the four small rectangles and arrange them to form a large square. Sketch each arrangement in a student's notebook.