Learn

In addition to `console`, there are other objects built into JavaScript. Down the line, you’ll build your own objects, but for now these “built-in” objects are full of useful functionality.

For example, if you wanted to perform more complex mathematical operations than arithmetic, JavaScript has the built-in `Math` object.

The great thing about objects is that they have methods! Let’s call the `.random()` method from the built-in `Math` object:

``console.log(Math.random()); // Prints a random number between 0 and 1``

In the example above, we called the `.random()` method by appending the object name with the dot operator, the name of the method, and opening and closing parentheses. This method returns a random number between 0 (inclusive) and 1 (exclusive).

To generate a random number between 0 and 50, we could multiply this result by 50, like so:

``Math.random() * 50;``

The example above will likely evaluate to a decimal. To ensure the answer is a whole number, we can take advantage of another useful `Math` method called `Math.floor()`.

`Math.floor()` takes a decimal number, and rounds down to the nearest whole number. You can use `Math.floor()` to round down a random number like this:

``Math.floor(Math.random() * 50);``

In this case:

1. `Math.random` generates a random number between 0 and 1.
2. We then multiply that number by `50`, so now we have a number between 0 and 50.
3. Then, `Math.floor()` rounds the number down to the nearest whole number.

If you wanted to see the number printed to the terminal, you would still need to use a `console.log()` statement:

``console.log(Math.floor(Math.random() * 50)); // Prints a random whole number between 0 and 50``

To see all of the properties and methods on the `Math` object, take a look at the documentation here.

### Instructions

1.

Inside of a `console.log()`, create a random number with `Math.random()`, then multiply it by `100`.

2.

Now, use `Math.floor()` to make the output a whole number.

Inside the `console.log()` you wrote in the last step, put the existing `Math.random() * 100` code inside the parentheses of `Math.floor()`.

3.

Find a method on the JavaScript `Math` object that returns the smallest integer greater than or equal to a decimal number.

Use this method with the number `43.8`. Log the answer to the console.

4.

Use the JavaScript documentation to find a method on the built-in `Number` object that checks if a number is an integer.

Put the number `2017` in the parentheses of the method and use `console.log()` to print the result.

# Take this course for free

By signing up for Codecademy, you agree to Codecademy's Terms of Service & Privacy Policy.

## Or sign up using:

Already have an account?