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src/edu/en/ethereum/Transactions/cancelling-speeding-up-transactions.md

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+# Cancelling/Speeding Up Transactions
+
+Ethereum allows users to manage pending transactions by either speeding them up or canceling them. Both of these options rely on using the **same nonce**, a unique counter for each transaction coming from your wallet:
+
+**Speeding Up:** If a transaction is taking too long, you can speed it up by sending a new, identical transaction with a higher gas price. Since both transactions share the same nonce, the network will prioritize the faster one with the higher fee.
+
+**Cancelling:** To cancel a transaction, you can send a new transaction with the same nonce, usually to yourself, with a higher gas price and no meaningful action (such as sending 0 ETH to your own address). This replaces the pending transaction, effectively canceling it.
+
+The **nonce** isn’t a unique transaction ID like the ones shown in blockchain explorers; rather, it’s a counter for each transaction from a specific wallet. The first transaction you send has a nonce of 0, the next is 1, and so on. By reusing the same nonce, you can replace or cancel a pending transaction before it is confirmed.
+
+Not all wallets support these features, so it’s good to check if yours allows for speeding up or canceling transactions.

src/edu/en/ethereum/Transactions/complexity-of-transactions.md

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+# Complexity of Transactions
+
+Not all transactions on Ethereum are alike. Some are straightforward, like sending ETH from one address to another, which involves just a single step.
+
+However, many transactions are more complex, especially those that involve interaction with decentralized apps (dApps) or smart contracts. For example, if you’re using a decentralized exchange (DEX) to swap tokens, a single transaction can trigger multiple steps—each managed automatically by Ethereum. Although complex behind the scenes, these actions are presented as one transaction to users, with Ethereum handling all steps in the background.
+
+More complex transactions take more computational resources on the side of validators and therefore more expensive to process. For instance a transaction, that may involve using some storage space on blockchain or perform extensive computation will be very expensive.

src/edu/en/ethereum/Transactions/transaction-fees.md

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+# Transaction Fees
+
+Every transaction on Ethereum requires a fee, paid in ETH, which goes to validators who maintain the network. Here’s how these fees work:
+
+- **Gas and Gas Limit:** Ethereum uses a system called “gas” to measure the effort a transaction needs. Simple transactions, like sending ETH, require less gas, while complex transactions involving smart contracts need more. The **gas limit** is the maximum gas a user is willing to pay for a transaction.
+
+- **Gas Price:** The gas price is how much ETH you’re willing to pay per unit of gas. When the network is busy, gas prices rise, as users compete to get their transactions processed faster. Most wallets estimate gas prices for you, but you can adjust them for speed. For example, during periods of high demand, fees may reach $100 or more for transactions like token swaps.
+
+- **Wallets’ Role in Estimating Fees:** Wallets automatically suggest a gas price and limit based on network activity, making things easier. Users can often adjust fees manually if they want to speed up or slow down a transaction. In fact most wallets won't even show these notions to the user and simply display the approximate amount in $USD the user is expected to pay for a transaction. The user simply moves the slider indicating the amount they are willing to pay in USD and everything else is handled by the wallet under the hood. Increasing transaction fee essentially increases the the gas price the user is willing to pay.
+
+In 2021, Ethereum’s EIP-1559 update introduced a **burn** mechanism, where a portion of transaction fees is permanently removed from circulation. This helps reduce ETH supply over time, especially during periods of high network activity when a lot of people are transacting. (EIPs, or Ethereum Improvement Proposals, are the system by which updates and new features are added to Ethereum.)

src/edu/en/ethereum/Transactions/transaction-statuses.md

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+# Transaction Statuses
+
+After you submit a transaction, it goes through a few phases before completion. Knowing these phases can help you track its progress:
+
+- **Pending:** Initially, a transaction enters the pending stage, waiting for a validator (similar to miners on Bitcoin) to include it in a block. If the network is busy, pending times can increase unless you’ve paid a higher gas price for priority.
+
+- **Confirmed:** Once a validator includes the transaction in a block, it becomes confirmed, meaning it’s completed, and the funds are transferred.
+
+- **Failed:** If there’s an issue, like running out of gas, the transaction may fail, and you’ll need to try again. Even for failed transactions, some gas fees may still apply, so it’s best to stick with the recommended fees unless you’re experienced and understand the steps involved.
+
+To check transaction status, you can use tools called **block explorers** like Etherscan or Blockchair. These let you view details about your transactions, including times, fees, and specific actions.

src/edu/en/ethereum/how-ethereum-works/eth-cryptocurrency.md

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+# ETH Cryptocurrency
+
+Ether (ETH) is the native cryptocurrency of the Ethereum platform. It functions both as a digital currency and as the fuel that powers the Ethereum network. Whenever you use Ethereum—whether to send ETH or interact with smart contracts —you need to pay fees in ETH.
+
+## Is Ethereum Inflationary or Deflationary?
+
+Unlike Bitcoin, Ethereum doesn’t have a fixed supply of ETH. Instead, new ETH is created at a changing rate, depending on network activity and other factors. Initially, Ethereum created around 18 million ETH per year, but this changed after it switched to Proof of Stake (PoS).
+
+In 2021, Ethereum introduced a system where part of the ETH used for transaction fees is **burned**, meaning it’s permanently removed from circulation. This reduces the supply, especially when there’s a lot of activity on the network.
+
+Ethereum can be **inflationary**(when more ETH is created than burned) or **deflationary**(when more ETH is burned than created). For example, in 2024, Ethereum became inflationary because more ETH was created than burned. However, during times of high network usage, like in early 2024, Ethereum was deflationary because more ETH was burned than emitted.
+
+Overall, whether Ethereum’s supply grows or shrinks depends on how busy the Ethereum network is and how much ETH gets burned compared to how much is created.

src/edu/en/ethereum/how-ethereum-works/how-ethereum-works.md

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+# How Ethereum Blockchain Works
+
+Both Ethereum and Bitcoin are made up of many computers all over the world, working together to maintain the blockchain and process transactions. The blockchain is a record of all transactions, and each computer has a copy of this record. To keep everything running smoothly, there needs to be a way to decide which computer will add the next set of transactions to the blockchain.
+
+Bitcoin uses something called **Proof of Work (PoW)**. Here, thousands of computers (miners) compete to solve a hard puzzle. The first one to solve it adds the next set of transactions and gets rewarded with newly created Bitcoin and fees. The more computing power you have, the better your chances.
+
+Ethereum used to work the same way, but now it uses something called**Proof of Stake (PoS)**. Instead of solving puzzles, people lock up (or “stake”) 32 ETH to become a validator. Validators are chosen randomly to add transactions to the blockchain, and they earn rewards in the form of ETH and fees. It’s random, so everyone who stakes has a chance.
+
+If you don’t have 32 ETH, you can join a **staking pool**. In a pool, lots of people combine their ETH to meet the 32 ETH requirement and share the rewards. This way, even if you don’t have a lot of ETH, you can still earn rewards.

src/edu/en/ethereum/how-ethereum-works/tokens-on-ethereum.md

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+# Tokens on Ethereum: ERC-20 & NFTs
+
+Ethereum is much more than its native currency, Ether (ETH). One of its standout features is the ability to create and manage tokens that represent different assets or utilities on the blockchain. These tokens are controlled by smart contracts and can be programmed by developers to serve specific purposes.
+
+For example, a token could represent a lottery entry, or give governance rights in a decentralized app (dApp). Two of the most widely used token types on Ethereum are **ERC-20 tokens** and **NFTs.**
+
+## ERC-20 Tokens
+
+ERC-20 tokens follow a widely-used standard that ensures all tokens created using this standard behave in a predictable manner. The common standard ensures that developers are able to build software apps (i.e. wallet apps, smart contracts) that can handle all tokens equally, rather than creating a separate wallet for each token. Also, tokens that follow ERC-20 standard are interchangeable, just like dollars, where one dollar is no different from another dollar. 
+
+Stablecoins like **USDT** or **DAI**, which are tied to the value of traditional currencies, and governance tokens like **UNI**, which grant users the right to participate in decision-making on Uniswap DEX(decentralized token exchange), are common examples of ERC-20 tokens. 
+
+These tokens can easily be transferred between Ethereum wallets and are compatible with a wide range of Ethereum-based apps and services, making them highly versatile and widely accepted across the network.
+
+## NFTs (Non-Fungible Tokens)
+
+NFTs, or Non-Fungible Tokens, are unique tokens that represent one-of-a-kind assets on the Ethereum blockchain. Unlike ERC-20 tokens, NFTs are not interchangeable, as each token is distinct. 
+
+NFTs have gained significant popularity in industries like digital art, collectibles, and gaming, where proving ownership of unique digital items is essential.
+
+NFTs can be used to represent anything from digital artwork to virtual real estate, and ownership is easily verifiable on the blockchain. This transparency has made NFTs a powerful tool for creators and collectors alike, providing a secure way to buy, sell, and trade digital assets.
+
+## Sending/Receiving ETH and ERC-20 Tokens
+
+Tokens on Ethereum, such as **USDT**, can be stored, sent, and received just like regular cryptocurrencies, such as **ETH** or **BTC**. One key aspect of Ethereum wallets is that both **ETH**and **ERC-20**tokens share a common wallet address. This means that within the same wallet, your deposit address for ETH is the same as for any ERC-20 token, like **USDT** or **DAI**.
+
+When sending ERC-20 tokens, it’s important to remember that **transaction fees must be paid in ETH**. This is because sending an ERC-20 token isn’t just a simple transfer—it involves interacting with the smart contract governing that specific token. For example, if you're sending **USDT**to someone, your wallet must interact with the USDT smart contract to complete the transaction, and the **gas fees** for that interaction are always paid in **ETH**.

src/edu/en/ethereum/how-ethereum-works/wallets-on-ethereum.md

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+# Wallets On Ethereum
+
+To interact with Ethereum, you need a non-custodial wallet app. An Ethereum wallet is an application that allows you to store, send, and receive Ether (ETH) and other Ethereum-based tokens. Most multi-currency, non-custodial wallet apps (e.g., Unstoppable Wallet) support Ethereum, making it easy for users to manage their assets on the platform.
+
+There are a few key things to keep in mind about Ethereum wallets:
+
+- **Single Address System:** Unlike Bitcoin, where a new address is generated for each transaction, Ethereum wallets typically use a single address for all your transactions. This means that all your Ethereum transactions and token balances are linked to the same public address.
+
+- **Types of Wallets:** Non-custodial Ethereum wallets come in various forms, including mobile apps, browser extensions, and hardware wallets. Among these, browser extension wallets are generally the least secure.
+
+- **Interacting with dApps:** Not all wallet apps come with the ability to interact with decentralized apps (dApps). While most wallets support basic send and receive functions, only certain wallets go further by allowing you to interact with dApps on the Ethereum blockchain. This functionality is usually provided through a feature called **WalletConnect**, which securely links your wallet to dApps. Not all wallet apps comes with **WalletConnect** feature.