We completed our example of the Honda driving off the lot and losing value immediately, as well as gradually depreciating each year. Alexa had to write an equation for the depreciation, given that it lost 9% of it's value after driving off the lot. She did a fairly good job of understanding the scenario.
I introduced the idea of decay and half-lives with the element radium. We looked at an example of radium decaying, and I explained that a half-life is the amount of time it takes for half of a substance to decay. For radium-226, it's half-life it 1600 years. Alexa and I explored questions about the appropriate domain for the situation.