# Python Reading

## Key Ideas

- A
**fraction** can be implemented as a class. A fraction
consists of two integers: a **numerator** and a **denominator**.
- An
**instance** of a class is **mutable**.
- A
**mutator method** is a method of a class that changes the
values of one or more **instance variables**.

## In-Class Activity

- Take a look at fraction.py.
- In the Fraction class, identify the
**instance variables**.
- In the Fraction class, identify the
**constructor**.
- For each method in the Fraction class, identify whether or not
it is a
**mutator** method.
- Trace what happens when the
**simplify** method is called when
the numerator value is 36 and the denominator value is 48.
- Explain why the
**add** method is correct.

## Active Learning

- Make sure you fully understand the fraction.py file. Ask questions
as necessary.
- Add a
**multiply** method to the program and test that it
works properly. Ask someone to check your solution.