Recognize that in a multi-digit number, a digit in one place represents 10 times as much as it represents in the place to its right and 1/10 of what it represents in the place to its left.

Imagine a world with no hundreds place. We'd have to call it *ten tens* instead. But then, what would we call the thousands place? How would we read 9999? What if we added *one more?*

Place value is something we cover in elementary school. It seems simple, but I'd wager that very few adults *really* understand the topic. I sure didn't until I worked with non-base-10 number systems in college. Your students can get a taste of this mind-boggling experience by imagining what it would be like if *we didn't have the number 9.* What would each digit represent then?