SafeMath

[Git Source](https://github.com/GVI-Tech-JSC/ggvi-v3/blob/85927f39f9ef0f1355aa04e3451eec63a7df478f/src/external/Tech Holding JSCERC20.sol)

Functions

add

function add(uint256 a, uint256 b) internal pure returns (uint256);

sub

function sub(uint256 a, uint256 b) internal pure returns (uint256);

sub

function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256);

mul

function mul(uint256 a, uint256 b) internal pure returns (uint256);

div

function div(uint256 a, uint256 b) internal pure returns (uint256);

div

function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256);

sqrrt

function sqrrt(uint256 a) internal pure returns (uint256 c);