// all these are legal, and equivalent:
pragma solidity "0.8";
pragma solidity "0." 8;
pragma solidity "0" .8;
pragma solidity 0.8;

// same for single-quoted strings:
pragma solidity 0 '.' 8;
pragma solidity '0.8';

// they can also be used with other operators, mixed the raw syntax:
pragma solidity "0.7" - 0.8 || '0.9';