Mastering Blockchain Programming with Solidity

Arithmetic calculation using SafeMath.sol

The SafeMath.sol library provides basic addition, subtraction, multiplication, division, and modulo mathematical calculation functions that can be used in your contract.

The OpenZeppelin contract present at Chapter09/openzeppelin-solidity/contracts/math/SafeMath.sol is defined as follows:

library SafeMath {    function mul(uint256 a, uint256 b) internal pure returns (uint256) {        if (a == 0) {            return 0;        }        uint256 c = a * b;        require(c / a == b);        return c;    }    function div(uint256 a, uint256 b) internal pure returns (uint256) {                require(b > 0);        uint256 c = a / b;                return c;    }    function sub(uint256 a, uint256 b) internal pure returns (uint256) {        require(b <= a);        uint256 c = a - b;        return c;    }    function add(