In this tutorial, we will learn about variables in Terraform. Variables are used to parameterize your configurations so that you can make them more flexible and reusable. We will cover the following topics: 1. Introduction to Variables 2. Declaring Variables 3. Providing Values for Variables 4. Default Values for Variables 5. Using Variables in Configurations 6. Output Variables 7. Variable Validations and Sensitivity 8. Example: Creating Multiple Subnets with Variables 9. Best Practices for Using Terraform Variables 10. Conclusion By the end of this tutorial, you will have a good understanding of how to use variables in your Terraform configurations.