_You can follow along with the video course from here._ ### Introduction In this section, we'll quickly summarize the lessons from 1 to 9 and learn about EVM and EVM-compatible blockchains. ### EVM EVM stands for _Ethereum Virtual Machine_. It's a decentralized computational engine that executes smart contracts. Any contract that it's written in Solidity, can be deployed to any EVM-compatible blockchain. Examples of such blockchains and Layer 2 solutions include **Ethereum**, **Polygon**, **Arbitrum**, **Optimism**, and **ZKsync**. > 🚧 **WARNING**:br > Although a blockchain like ZKsync may be EVM-compatible, it is essential to verify that all Solidity keywords are supported ### Contract Setup Before writing any smart contract, always specify the Solidity version you intend to work with. Additionally, include the SPDX license identifier at the top of your file. ```solidity // SPDX-License-Identifier: MIT pragma solidity >=0.7.0 <0.9.0; ``` Next, create a contract object. In Solidity, a `contract` is similar to a class in other programming languages. Everything within the curly brackets `{}` is part of the contract's scope. ### Types and Structures Solidity supports various primitive types such as `uint256` and `bool`, allows the creation of custom types with `struct`, and supports arrays and mappings. ### Functions and Behavior Functions in Solidity can modify the state of the blockchain and execute transactions. Functions that do not modify the blockchain’s state are declared with `view` or `pure` keywords. ### Data Locations and Memory Solidity lets you specify different data locations for strings, structs, and array variables. The terms `calldata` and `memory` denote temporary variables that exist only for the duration of a function call. Conversely, `storage` variables are permanent and remain in the contract indefinitely. Function parameters cannot be `storage` variables, as they exist only for the duration of the function call. When you compile your smart contract, the Solidity code is converted into EVM-compatible bytecode, which is machine-readable code. ### Conclusion Mastering the fundamentals of Solidity, including contract setup, data management, and function behaviors, provides a robust foundation for developing powerful decentralized applications. This foundational knowledge is essential for navigating the complexities of blockchain technology and leveraging its full potential. Well done! ### 🧑‍💻 Test yourself 🏆 Attempt to answer all questions from lesson 1 and then go back again to complete all the coding tasks.