More and More Efficient

Rose was 6 years and 7 months at the time that this video was made.

The Problem

There were 5 buses and there were 2 chickens on each bus. How many chickens are there altogether?

What To Look For In This Video

To model this problem one would first represent the 5 buses, then represent the 2 chickens on each bus, and then count the "chickens."
I think that Rose started out by counting on her fingers. I think that she was trying to keep track of how many sets of 2 she had counted and at the same time keep track of how many "chickens" altogether.
- One, two (that's one set of 2)
- three, four (that's two sets of 2)
- etc.
In other words, she was taking a shortcut by counting out the 5 buses, the 2 chickens on each bus, and the total number of chickens - all three counting tasks at the same time.
After a brief pause, I think that she realized that she could more efficiently solve the problem by counting by 2's.

So Rose has at least two shortcuts for solving this problem - one more efficient than the other.

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