𝗗𝗮𝘆 𝟯: Ether (ETH) ​If Ethereum is the "World Computer," Ether is the fuel that keeps the engine running. ​Ether is defined as the native cryptocurrency of the Ethereum ecosystem. But for builders, it’s much more than just money.  it is a utility token used to pay for computational resources. ​The Unit of Measurement (Precision matters)  In Ethereum development, we rarely work with just 1 ETH, Because smart contracts need to be incredibly precise, Ether is divisible down to 18 decimal places. ​The most important units you'll use in code are: - ​Wei: The smallest possible unit (1 \text{ Ether} = 10^{18} \text{ Wei}). Everything in the EVM is actually calculated in Wei.  - ​Gwei: Used mostly for gas fees (1 \text{ Gwei} = 10^9 \text{ Wei}). When you hear "Gas is 20," they mean 20 Gwei. ​Ether is The unit we see in our wallets. ​Why Builders Care: - ​Staking: Ether is used by validators to secure the network. - ​Gas: Every line of code you write costs a tiny bit of Ether to execute. - ​Value Transfer: It’s the default way to move value between accounts and contracts. ​- ​The Main Key Note: Ether isn't just a currency, it’s a meter tool. It prevents people from spamming the network with infinite loops and ensures every computation is paid for. - ​Tomorrow, we look at the unit that specifically measures that work: → Gas.