A LITTLE PRACTICE GOES A LONG WAY
Make it stick.
Six small challenges, from your first conversion to reading ABI offsets. Use the tools, take a hint, and try again.
How many Wei make 0.01 ETH?
Need a hint?
1 ETH is 10¹⁸ Wei. Divide that by 100.
What are the first 4 bytes of transfer(address,uint256), including 0x?
Need a hint?
Hash the canonical function signature with Keccak-256, then take four bytes.
21,000 gas at 12 Gwei per gas: what is the fee in ETH?
Need a hint?
Multiply 21,000 × 12 Gwei, then convert Gwei to ETH.
How many slots do uint128, uint128, uint256 need, in that order?
Need a hint?
The two uint128 values share one slot. The uint256 needs another.
setMessage(string) has one dynamic argument. What is the first word’s offset in decimal bytes?
Need a hint?
The head has one 32-byte word. The tail starts immediately after it.
Which ERC-20 function sets a spender’s allowance: transfer or approve?
Need a hint?
An allowance gives a spender permission. A transfer moves tokens directly.