In this clip the teacher is discussing the formula from the previous clip with a group that is having trouble understanding the formula.
Fractional Exponents, Clip 1, 4:20
To begin with it's important as a class to make the decsion about what it means to talk about parts of a penny. In this case the teacher makes it explicit.
Notice how the teacher has a discussion with astudent, gives her a way to check her answer, but does not give her the answer. It is important that the students take ownership of performing the mathematics.
The students have an opportunity to develop the formula for doubling time and it’s important the teacher helps guide their thinking without solving the problem for them. Notice the teacher has the students check their answers. This is an often overlooked step in solving mathematical problems.
