    function _rewardPerToken(address _rewardsToken) internal view returns (uint256) {
        if (lockedSupply == 0) {
            return rewardData[_rewardsToken].rewardPerTokenStored;
        }
        return
            uint256(rewardData[_rewardsToken].rewardPerTokenStored).add(
                _lastTimeRewardApplicable(rewardData[_rewardsToken].periodFinish)
                    .sub(rewardData[_rewardsToken].lastUpdateTime)
                    .mul(rewardData[_rewardsToken].rewardRate)
                    .mul(1e18)
                    .div(lockedSupply)
            );
    }
(now - lastUpdateTime) * rewardRate * 10**18 / totalSupply
(now - lastUpdateTime) * rewardRate * 10**18 / totalSupply => 10**5 * 10**12 * 10**18 / 1 = 10**35
                uint256 newRewardPerToken = _rewardPerToken(token);
                rewardData[token].rewardPerTokenStored = newRewardPerToken.to96();
