A suggested 20-minute session for an association, a class or a friend. Discuss fictional situations without buying crypto, creating an account or connecting a wallet. Allow more time if the vocabulary is new.
Answers and sources: whytheblockchain.com/en/teach
0–3 min
Explain the three words below. No one needs to own crypto.
3–8 min
Calculate the purchase cost together. Ask everyone to explain their calculation.
8–15 min
Discuss the permission and the network. Show the answers after the discussion.
15–20 min
Each person picks one check they can now explain. Continue with a full exercise if needed.
Three words before you start
A wallet is an app or device that manages the keys used to authorise actions. A token is a digital unit recorded on a network. A network is the system that records and checks transactions; Ethereum and Base are examples of different networks.
You spend €100. The purchase commission is 1% of that amount. Withdrawing to your wallet costs another €2. Assume the crypto price stays the same and there is no price markup (spread). These prices are fictional.
What value reaches the wallet? Show the two deductions.
Show the answer and explanation
1% of €100 is €1. After the purchase, €99 remains. Subtracting the €2 withdrawal fee leaves €97 worth of crypto. With real services, check the final quote: the asset price, fees and spread can all change the result.
You plan to exchange 25 USDC tokens on a site. Your wallet displays a spending approval for 250 USDC. USDC is a token designed to track the US dollar. The amount of the approval is a spending limit for a contract, not necessarily an immediate payment.
What do you check before approving? Would disconnecting the site later cancel this permission?
Show the answer and explanation
Pause and check the site, the token, the network, the contract receiving permission and the amount. A higher limit alone does not prove a scam, but it exceeds your intended 25 USDC. In this scenario, reject the request and investigate. Disconnecting the site does not revoke an existing token approval. Revocation is a separate action and usually requires a network transaction.
Your sending screen says “USDC — Ethereum”. The receiving instructions say that this deposit supports USDC only on Base. These are two different networks. This is a fictional receiving service; always read the actual recipient’s instructions.
Can you send as shown just because both sides say USDC?
Show the answer and explanation
No. The selected sending network does not match the supported receiving network. Stop here and verify a compatible deposit route with the recipient or service. Do not guess, and do not send a small test over this unsupported route. Even if an address has the same format on both networks, that does not establish deposit support.
Ask people to explain why, rather than awarding a score. If someone has a real transfer problem, stop the simulation and use the relevant provider’s official support. Never collect recovery phrases, private keys or screenshots containing secrets.
You may print and share this worksheet for a free educational workshop, with the WhyTheBlockchain credit and source link retained. The worksheet is general education, not a security audit or an investment recommendation.
