This worksheet on the Latin word root uni should serve students well, particularly English language learners. It means, of course, one. This is an extremely florid root in English, showing up all over the place, and in words across the common branch curriculum.
If you find typos in this document, 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.