NoMulDiv

// SPDX-License-Identifier: MIT
// compiler version must be greater than or equal to 0.8.13 and less than 0.9.0
pragma solidity ^0.8.9;

contract HelloWorld {
  string public greet = "Hello World!";

  function claim(
    uint256 numPasses,
    uint256 amount,
    uint256 mpIndex,
    bytes32[] calldata merkleProof
  ) external payable {
    require(isValidClaim(numPasses,amount,mpIndex,merkleProof));

    //return any excess funds to sender if overpaid
    uint256 excessPayment = msg.value.sub(numPasses.mul(mintPasses[mpIndex].mintPrice));
    (bool returnExcessStatus, ) = _msgSender().call{value: excessPayment}("");

    mintPasses[mpIndex].claimedMPs[msg.sender] = mintPasses[mpIndex].mulDivRoundUp(numPasses, 3);
    _mint(msg.sender, mpIndex, numPasses, "");
    emit Claimed(mpIndex, msg.sender, numPasses);
  }
}

// SPDX-License-Identifier: MIT
// compiler version must be greater than or equal to 0.8.13 and less than 0.9.0
pragma solidity ^0.8.9;

contract HelloWorld {
  string public greet = "Hello World!";

  function claim(
    uint256 numPasses,
    uint256 amount,
    uint256 mpIndex,
    bytes32[] calldata merkleProof
  ) external payable {
    require(isValidClaim(numPasses,amount,mpIndex,merkleProof));

    //return any excess funds to sender if overpaid
    uint256 excessPayment = msg.value.sub(numPasses.mul(mintPasses[mpIndex].mintPrice));
    (bool returnExcessStatus, ) = _msgSender().call{value: excessPayment}("");

    mintPasses[mpIndex].claimedMPs[msg.sender] = mintPasses[mpIndex].mulDivRoundUp(numPasses, 3);
    _mint(msg.sender, mpIndex, numPasses, "");
    emit Claimed(mpIndex, msg.sender, numPasses);
  }
}