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## Introduction to JavaScript

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1. JavaScript: Basics
9Topics
|
10 Quizzes
2. JavaScript: Variables
9Topics
|
10 Quizzes
3. JavaScript: Conditional Statements
10Topics
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11 Quizzes
4. JavaScript: Functions
10Topics
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11 Quizzes
5. JavaScript: Scope
6Topics
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7 Quizzes
6. JavaScript: Arrays
11Topics
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12 Quizzes
7. JavaScript: Loops
8Topics
|
9 Quizzes
8. JavaScript: High Order Functions
3Topics
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4 Quizzes
9. JavaScript: Iterators
3Topics
|
3 Quizzes

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Lesson 1, Topic 9
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# JavaScript: Built-in Objects

##### abeerairfan 27 Oct 2021
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Aside from the console, JavaScript includes a number of other objects. You’ll eventually create your own objects, but for the time being, these built-in objects are ready-to-use features.

For example, if you need to perform more complex mathematical operations than arithmetic, JavaScript includes the Math object.

Objects have methods, which is fantastic! Let’s use the Math object’s built-in `.random()` method:

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

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

We could multiply this result by 100 to get a random number between 0 and 100:

``console.log(Math.random()*100); // Prints a random decimal number between 0 and 100``

The above example will most likely be evaluated to a decimal. To ensure that an answer is a whole number, we can use another useful Math method called` Math.floor()`.

`Math.floor()` is a function that takes a decimal number and rounds it down to the nearest whole number. To round down a random number, use `Math.floor()` as shown below:

``console.log(Math.floor(Math.random() * 100)); // Prints a random whole number between 0 and 1``

In this case:

• `Math.random` generates a random number between 0 and 100.
• We then multiply that number by `100`, so now we have a number between 0 and 100.
• Then, `Math.floor()` rounds the number down to the nearest whole number.
• `console.log()` prints the result on terminal.
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