4-Calculator-Solution.sol

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

// 0. Make a contract called Calculator ✅
// 1. Create Result variable to store result ✅
// 2. Create functions to add, subtract, and multiply to result ✅
// 3. Create a function to get result ✅

contract Calculator {

    uint256 result = 0;

    function add( uint256 num) external {
        result += num;
    }

    function subtract(uint256 num) public {
        result -= num;
    }

    function multiply(uint256 num) public {
        result *= num;
    }

    function get() public view  returns (uint256) {
        return result;
    }

}