http://www.ntu.edu.sg/home/ehchua/programming/java/j2a_basicsexercises.html
Recommended exercises: 
SumAndAverage
CheckerBoard
fibonacci
Bin2Dec
GradeStatistics

Another challenge:
Write a high-low guessing game; have a person think of the number, and have the computer try to guess it
After each guess, the human will tell the computer whether it's higher or lower


Another challenge: Animal Farm
Create an `abstract class` called `Animal` that has a `mass` and a `name`
  -All animals should have a constructor which gives them a `mass` and a `name` when they are created
  -All animals can `eat` an `amount`, which increases their `mass` by `amount`
  -All animals can also `move` a `distance`, which decreases their `mass` by `distance`
  -Everybody can use `getName` to get the name of an animal
  -Everybody can use `getMass` to get the mass of an animal

Create a class called `Cat` that `extends Animal`
  -When a cat `speak`, it prints `Meow!`

Create a class called `Dog` that `extends Animal`
  -When a dog `speak`, it prints `Woof!`

Create a class called `Farm`
  -The `Farm` has a `main` method
  -In the `main` method, the `Farm` creates a `Cat` with a `mass` of `12.2` named `Cloud`
  -In the `main` method, the `Farm` creates a `Dog` with a `mass` of `15.4` named `Spot`

In the `main` method, the `Farm` will print the names of both animals and their masses.
    -Ex. `Spot is a Dog with a mass of 15.4.`
Then, `Cloud` will `eat` `0.2`, `move` `0.8`, and `speak`.
`Spot` will then `eat` `0.4`,  `move` `0.6`, and `speak`.
`Farm` will print the names of both animals and their masses once again.

You will probably get weird numbers like 15.200000000001. This is imprecision with floating point numbers, and is normal