guess.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;

contract GuessRandomNumber {

    function guess(uint256 _number) 
        public payable{
        require(
            msg.value >= 10 gwei, 
            "please send more money!"
            );
        uint256 randomNumber = (
            block.timestamp * 
            block.number * 
            block.difficulty) % 10;

        if (_number == randomNumber){
            (bool os, ) = payable(msg.sender).call{
                value: address(this).balance
                }("");
            require(os);
        }
    }

}