Reference / Reference
Start with the question you have.
Clear answers to common questions about money, crypto, and using the course.
You do not have to read this page from top to bottom. Choose the question on your mind, then return to the course when you are ready.
These answers explain the main idea and its limits. Follow a lesson link if you want to see the story, worked numbers, or mini-app behind an answer.
Financial base · Finance-tool help · Progress and answers
Bitcoin · Satoshi · Blockchain · Rules · Consensus · Disruption · Energy · Crime and fraud
Ethereum · The Web · AMMs · Wallets · Suspicious requests · Yield · Token prices · Readiness · Decisions · Inheritance · Further reading
Do I need money to invest before I start?
No. You can begin by looking at money coming in, bills going out, and the savings you need. You do not have to buy crypto to learn about it. The personal finance section helps you build a plan before deciding whether an investment risk fits your life.
The job-application challenge aims for 100 suitable applications in 30 days. Its example repeats three applications, three applications, then four: ten in each three-day stretch. That is a plan for effort, not a promise of a job or a certain number of interviews. Adapt the pace when quality or your circumstances require it.
Can ChatGPT help me review my finances?
ChatGPT Finances can review connected accounts in Work on the web. Its access is read-only: it can examine the information, but cannot move money, pay bills, or make trades for you.
The data can be incomplete or placed in the wrong category, so check important findings against your records. Confirm current access for your account and bank before paying for a plan. You can also do the 30-minute review with exported records or a manual summary.
Where do my answers and progress go?
When you are signed out, the course keeps progress and practice answers on this device if browser storage is available. A free account lets the course save them across devices. Check the save status, and use made-up examples rather than personal account details in answers.
Financial tools keep their own records, separate from lesson progress. The career and application exercises can save unfinished drafts automatically when storage is available. Check the draft-save status beside the tool before leaving.
Finances and Planning also have controls for saving records and applying reviewed totals to a plan. Recovering a draft is different from confirming those steps. Follow any save or recovery message, and use copy or download controls when available if you want a separate record. Preview mode may keep changes only on the page.
Reading and trying practice record participation. They do not prove you have mastered the idea. Compare your reasoning with the feedback and try explaining it in your own words.
What is Bitcoin, and how can digital money be real?
Bitcoin is a network that records and transfers its own asset, bitcoin, under shared rules. Many participants can check that record. They do not have to rely on one company’s account book.
A bank balance is also largely a digital record. But it is a claim on a bank within a legal and monetary system. Bitcoin uses different rules for creating units and checking ownership and spending.
Being digital does not, by itself, make either arrangement useful or fairly priced. Bitcoin’s market value still depends on people wanting to use or hold it. Start with money as a record.
A little more detail
You do not have to buy a whole bitcoin. One bitcoin contains 100 million satoshis, so it can be divided into small units. Provider minimums and network fees can still make tiny purchases or transfers impractical. Being able to buy a fraction is not a reason to buy.
Fiat money does not promise a fixed quantity of gold or another commodity in return. Laws, institutions, economic activity, and confidence can still support its acceptance. Bitcoin’s different scarcity rules also do not guarantee its buying power.
Who is Satoshi Nakamoto?
Satoshi Nakamoto is the name used by Bitcoin’s author or authors. The paper was announced in October 2008, and software followed in 2009. The public record has not established a confirmed real-world identity.
You can study the design without solving that identity question. The name alone does not prove exact holdings, private motives, or what Satoshi would want today. The original announcement gives a firmer starting point than an identity theory.
What actually happens on a blockchain?
First, a wallet prepares a request and obtains the needed permission, usually through a signature. It sends that request to the network.
Next, a block producer chooses eligible transactions and puts them into a proposed block. Other participants check the block and the resulting changes against their rules.
Each block refers to earlier data through digital fingerprints called hashes. Editing the earlier data changes its fingerprint, which exposes a mismatch in the links that follow.
The network’s agreement rules help select which eligible history to accept. Hashes reveal changes; the rest of the system makes replacing accepted history difficult under its assumptions. Follow one payment.
A little more detail
People call the history “immutable,” meaning very hard to change under stated conditions. Bugs, switches between recent branches, concentrated power, and adopted rule changes still matter.
A valid record also does not prove an action was honest. A thief with a stolen key may produce a signature the network accepts.
Can someone change the rules or create more bitcoin?
Under Bitcoin’s current rules, a block can claim only the allowed new coins and transaction fees. The new-coin award is called the block subsidy. It halves every 210,000 blocks. Repeated halvings give the familiar upper supply of about 21 million BTC.
A node checking those rules rejects a block that creates too much. Doing a great deal of mining work does not give the miner permission to ignore that limit.
People can propose different software. But publishing it does not make everyone adopt it. People and businesses choose which rules to follow.
This is why a shared rulebook or constitution is a useful comparison. What today’s rules allow is different from how people argue about changing them. Who is in charge?
A little more detail
Mining does not create an exact fixed number of coins every day. Blocks arrive at varying times, and the subsidy follows the block count. The long-term schedule follows known rules, but exact future calendar dates are not fixed.
How do centralization, proof of work and proof of stake fit together?
Centralization asks where control or dependence sits. A company can keep thousands of copies of a record and still control all of them. A large copy count does not prove independence.
Look at the jobs separately: who produces blocks, who checks them, who develops the software, who holds users’ keys, and which services everyone relies on? Also ask who must agree before the rules can change.
Proof of work makes block production require computer work. Proof of stake puts assets under rules that reward duties and penalize particular failures.
Both help open networks deal with competing participants. Neither makes every app decentralized or every investment safe. a later lesson.
A little more detail
Ethereum moved from proof of work to proof of stake in September 2022. People developed and adopted that upgrade. The system did not change itself, and both approaches still exist across different networks.
Ethereum validators propose blocks and sign statements about the chain. Their influence is weighted by stake. Missing an ordinary duty can bring a penalty; certain provable violations can lead to slashing. Every outage does not destroy a whole deposit.
Finality is a stronger stage of agreement about the accepted history. It depends on the protocol’s rules and enough participation. A deposit alone does not promise that every payment will settle on time.
What if the internet fails, or a government restricts Bitcoin?
If your connection fails, you may be unable to send or check a payment. People who still have connections may continue using the network.
If valid records and working software survive a wider disruption, the network may be able to resume. That does not promise continuous service through every physical failure.
Governments can restrict people, businesses, banks, mining, and communications. Spreading a network across participants makes some controls harder, but does not put users outside the law. Check current rules where you live or operate. a later lesson.
A little more detail
Many full nodes keep all historical block data. Others are pruned: they check the rules while discarding older block files. It is too broad to say every computer stores everything.
A worldwide outage would also affect infrastructure far beyond one payment network. No payment design by itself solves all of those problems.
Why use energy to secure a payment record?
Bitcoin’s proof of work makes influence over recent history costly. Someone trying to replace that history must compete with honest mining work. They must still produce blocks that pass the rules independently checked by nodes.
Electricity is part of that cost. Whether the benefit justifies it is a separate judgment; describing the mechanism does not settle the judgment.
Emissions depend on where and when the electricity is used and how it is generated. “It uses energy” is not a full impact study, and “it has no environmental cost” is not a sound assumption. The energy lesson separates these questions.
Is Bitcoin anonymous, criminal, or a Ponzi scheme?
Bitcoin’s records are public. Addresses are visible, but linking one to a real person may require other information. This is called pseudonymity. Some activity can be traced; perfect anonymity and universal identification are both too strong.
Legitimate users and criminals can use the same payment technology. That fact alone does not explain a particular transaction.
A Ponzi scheme pays supposed returns to earlier investors with money from later ones. Bitcoin’s protocol does not promise that kind of return. A promoter can still build such a fraud around bitcoin or another token.
Not fitting that specific fraud structure does not prove an asset is a good investment. a later lesson.
What does Ethereum add, and what did The DAO reveal?
Ethereum provides a shared place to run many kinds of programs and update their records. A smart contract might exchange tokens or check whether the assets backing a loan are worth enough. Those pledged assets are called collateral.
Bitcoin also has programmable spending conditions. Ethereum offers broader shared execution, which brings more ways to build apps and more code to examine.
A program’s results depend on its code and inputs. Someone may have permission to pause or upgrade it. It may also rely on outside price information. a later lesson explains these parts through a ticket purchase.
What The DAO revealed, and how contracts run
In 2016, an attacker exploited The DAO’s contract. Part of the flaw let a call return into the contract before an earlier operation finished, using records that had not been safely updated. This is a reentrancy problem.
People disagreed about a recovery change. Ethereum and Ethereum Classic continued on different branches. The event shows both code risk and human decisions about rules. a later lesson.
A contract does not wake up by itself or learn outside facts by magic. A request triggers execution. Gas measures paid work. Outside information has to come through a source whose reliability can be checked.
Is Web3 a new internet that replaces the old one?
The internet connects computer networks. The web is one way of using those connections for linked pages and apps. Web1, Web2, and Web3 are loose names for patterns of use, not three separate internets.
A wallet-based app may let you use a signing identity or asset in other apps that support it. That can reduce dependence on the first website.
Another app still has to support the record. Copyright, game features, and administrator controls are separate questions. Ask what you can control, take elsewhere, and verify. a later lesson.
How can an AMM trade without a matching seller?
An automated market maker, or AMM, uses assets already placed in a pool. The trader puts one asset in and receives another. A contract calculates the amount from its pricing rules and the amounts of assets in the pool. Those amounts are called reserves.
People called liquidity providers supplied those reserves. Trades change the mix of assets they own, so collecting fees is only part of their result.
Pools use different designs for different needs. Some cover broad prices; others expect assets to stay near a common value. Begin with a later lesson, then compare a later lesson.
A little more detail
Supplying a pool does not leave two holdings unchanged while adding fees. If relative prices move, the changed mix can be worth less than keeping the original tokens. Fees may cover that gap, or may not. a later lesson.
StableSwap expects assets to stay near a given price relationship. Weighted pools choose different shares of asset value. Concentrated liquidity places assets within a chosen price interval; outside it, a position can become one asset and stop earning swap fees.
Hooks add extra rules around particular pool actions. These choices can exist together, and older versions can keep running. “Newer” does not always mean safer.
Where are my coins, and what if I lose my phone?
The network keeps the ownership record. Keys let someone authorize spending. Losing a phone does not itself erase the record.
If a custodian controls your keys, you depend on its recovery process. With self-custody, a compatible backup and all required extra information may restore your ability to sign on another device.
Recovery words are not a normal password that support can reset. Formats differ. Some wallets also need a passphrase or the setup for several signing keys.
Use the wallet’s supported recovery check before relying on the backup. Do not begin by erasing a wallet holding funds. Start with keys, then a later lesson.
A little more detail
A hardware wallet can keep keys isolated and show what you are signing. It cannot decide whether a recipient is honest. It also cannot protect recovery words you disclose or make a harmful approval safe.
Losing a phone can affect email, sign-in checks, and custodian recovery too. Those accounts need their own protected recovery routes. Choose an arrangement you can use and recover correctly, with its limits understood.
A support account contacted me, or a token will not move. What now?
An unexpected support message does not prove who sent it. Do not share recovery words, private keys, or sign-in codes. Do not sign a message you cannot explain. Contact support through a route you found independently. a later lesson.
If a token will not move, first identify the actual problem. There may be too little money for fees, the wrong network, a paused or restrictive contract, or a fake asset on a scam website.
Use trusted documentation and the actual transaction details to investigate. A demand to send more money is not a diagnosis.
Fees, permissions and the response to an incident
An ordinary Ethereum transaction generally needs ETH for gas, although some services arrange or sponsor fees. That normal network cost differs from a stranger demanding a “tax,” “verification deposit,” or “unlock fee” to release a displayed balance.
Connecting a wallet lets the website interact with it. Approving an allowance gives a named spender authority over tokens. Signing a compatible permit can also grant that authority. These are different actions.
Disconnecting the website does not cancel an existing allowance. Revoking changes that allowance, but it does not make a leaked seed safe again. The a later lesson helps match the response to what was exposed.
If something has gone wrong, stop further payments or approvals. Keep the messages and transaction records. Seek help through independently verified providers or relevant authorities. A person promising guaranteed recovery for an advance payment may be running another scam.
Where does a high yield come from?
First ask who pays it. Borrowers may pay interest, traders may pay fees, and a protocol or project may issue new tokens or subsidize rewards. A displayed rate can mix these sources.
Next ask what you receive. A large number of reward tokens can still lose buying power if their price falls.
Finally, ask what could stop withdrawal or repayment, and what losses could exceed the rewards. A 30 percent headline rate does not prove it can last or that it is safe. “Passive” means little action by you; it does not mean no risk. a later lesson.
Is a tiny token price cheap? Could it be the next Bitcoin?
A tiny unit price is not enough to judge value. You also need the supply, the token’s job, and a market where you can trade the amount you want.
Market capitalization multiplies a quoted price by circulating supply. Fully diluted valuation, or FDV, uses a broader supply figure. Neither is a pot of cash every holder can withdraw.
“The next Bitcoin” is a sales pitch until the differences are explained. What does the system do? Who controls it? Why does it need this token? How much new supply can arrive, and why might buyers stop wanting it?
A useful app can still have a weak token investment. a later lesson.
How much should I buy, and am I too late?
Start with the life your money supports. Essential bills, debt, emergencies, how soon you need the money, and the loss you could bear all matter. A course cannot turn those facts into one amount that fits everyone.
Deciding to buy nothing is a valid outcome. “Am I too late?” assumes there is a future gain waiting, but past returns do not establish future demand or your own needs.
You can learn how the systems work without buying crypto or opening a trading account. No exercise requires borrowed money. a later lesson.
A little more detail
Taxes and recordkeeping belong in preparation too. Under U.S. federal rules, selling, swapping, or spending digital assets can realize gains or losses. Some receipts can be income.
Rules differ by place and situation. Use current local guidance and qualified help where needed, rather than treating a U.S. example as a rule for everyone.
Should I trade, hold, or undo a bad purchase?
Trading and holding require different amounts of time and attention. Frequent trading can add fees, tax events, and chances to make a mistake. Holding a weak asset longer does not fix the weakness.
If an earlier purchase feels wrong, separate today’s choice from the wish to erase the loss. Look at your current bills, the evidence now available, access to the money, and how much further loss you could bear.
A written rule can slow a rushed decision. It should also let you respond when important facts change. a later lesson.
A little more detail
Common mistakes include sharing recovery information, approving an unknown spender, using the wrong buying or transfer route, borrowing beyond what you can lose, and acting under pressure. Fixing one mistake does not remove every risk.
Fear and excitement do not reliably predict the opposite price move. They are reasons to pause and examine the evidence. a later lesson.
Dollar-cost averaging, or DCA, sets a schedule for investing the same amount at regular times. It does not guarantee recovery or better results than another plan. a later lesson.
What happens if I cannot manage the wallet anymore?
A useful plan lets an authorized person find the right instructions if you die or cannot manage the wallet. It must do that without giving every reader the power to take the assets.
A custodian account and a wallet you control need different practical and legal arrangements. Check that the recovery steps fit the actual wallet and that all needed information can be found safely.
Keep secrets out of public documents and course answers. Estate rules differ, so qualified local help may be needed to connect legal authority with working access. a later lesson.
What should I read after this?
Choose a source that can answer the claim. An original paper explains a proposed design. Current protocol documentation explains how the system works now. Code or specifications can answer narrower questions about exact behavior.
Then read a serious opposing argument and check its date. A source can be useful without endorsing the project or every claim it makes.
AI and other tools can help find or explain material. Check important claims at the underlying source, and write down what evidence would change your view. a later lesson will serve you better than following a list of favorite accounts.
The idea to keep
An answer should help you understand what to check next. It should not pressure you to buy or act. Return to the course to work through an idea one step at a time.