One is one … or is it?

One bag of apples, one apple, one slice of apple — which of these is one unit? Explore the basic unit of math (explained by a trip to the grocery store!) and discover the many meanings of one.

Lesson by Christopher Danielson, TED-Ed 製作的動畫.

View the full lesson: http://ed.ted.com/lessons/one-is-one-or-is-it