In learning the power of 10, what must students grasp about teen numbers?

The understanding of teen numbers is crucial when learning about the power of 10. Teen numbers, which range from 10 to 19, are comprised of a base value of 10 plus an additional digit that typically ranges from 0 to 9. This means that a teen number can be thought of as simply the number 10 with an extra value added. For example, the number 13 is made up of 10 plus 3. Recognizing this structure helps students to better grasp the relationship between numbers and enhances their understanding of the place value system as it applies to larger numbers.

The other options misinterpret the characteristics of teen numbers: they do not consistently represent values greater than twenty, they can be either even or odd, and they certainly include non-prime numbers. Therefore, understanding that teen numbers is fundamentally about having a base of 10 plus a digit solidifies a foundational concept in number comprehension.