Modeling - Hard Addition

Trixie was 3 years and 4 months at the time that this video was made.

The Problem

Suppose that I have 2 pennies. And suppose that you have 3 more pennies than I have. How many pennies do you have?

What To Look For In This Video

Once again, I believe that the only sensible thing for me to do is to show her what I mean by working with her to make the model.