This activity/post is a little different than are usual posts. We look at a particular math concept and consider how to use context, models and CCSS math practices to increase student understanding. This activity focuses on negative exponents. Even if you aren't teaching negative exponents, this is a great opportunity to look at non-linear growth or positive exponents.
We use examples of a plant and a beanstalk growing exponentially and ask kids to determine the height of these plants in the future (growing at the same rate). Students skip ahead several inputs and are forced to consider a rule to model the situation.