solidity问题 from solidity: ParserError: Function, variable, struct or modifier declaration expected.

Question

你们好，我是solidity初学者，现在在打一个代码时候遇到了一个困难。一直出现from solidity:
ParserError: Function, variable, struct or modifier declaration expected.这个信号。但是我检查过了，并没有缺少什么花括号东西。
以下是我的代码
// SPDX-License-Identifier:MIT
pragma solidity ^0.8.0;

contract math{
uint numa = 4; //int256==int
uint numb = 2; //uint256==uint

function add(uint a,uint b) pure  public returns(uint){
     return a+b;
}
function jian(uint a,uint b) pure public returns(uint){
     return a-b;
}
function cheng(uint a,uint b) pure  public returns(uint){
     return a*b;
}
function chu(uint a,uint b) pure  public returns(uint){
     return a/b;
}
function yu(uint a,uint b) pure public returns(uint){
     return a%b;
}
function pingfang(uint a,uint b) pure public returns(uint){
     return a**b; 
}

    uint8 a = 3;
    uint8 b = 4;
    function weiyu()  public view returns(uint){
        return a & b;
    }
    function weihuo() public view returns(uint){
        return a  | b;
    }
    function weifan() public view returns(uint){
        return ~a ;      //取反
    }
    function weifei() public view returns(uint){
        return a ^ b;   //取非
    }
     function zuoyi() public view returns(uint){
        return a<<1;   //左移
    }
     function youyi() public view returns(uint){
        return a>>1;   //右移动
    }
   }

Answer 1

入参和预设参数名称重复了。