The reading covers the five types of angles in geometry: acute (1-89 degrees); right (90 degrees); obtuse (91-179 degrees); straight (180 degrees); and reflex (180-359 degrees). This is an exercise designed to supply diverse learners with practice manipulating two symbolic systems–i.e. words and numbers–at the same time. It also, I would think (but also qualify this with something that is beyond dispute–I am not a teacher of mathematics), introduces students to the concept of angles in geometry.
For more on the material I developed from Barbara Anne Kipfer’s superb reference book The Order of Things, see the About Posts & Texts page visible on the masthead of the home page of this blog.
If you find typos in these documents, I would appreciate a notification. And, as always, if you find this material useful in your practice, I would be grateful to hear what you think of it. I seek your peer review.