"Unknown price" trading principle: investors can't know the trading price immediately when buying and redeeming. The subscription and redemption prices can only be calculated on the basis of the net value of fund shares announced by the fund manager after the end of trading hours on the day of subscription and redemption.
The principle of "amount subscription and share redemption": the subscription is applied according to the amount, and the redemption is applied according to the share. This is the simplest and safest way to deal with "unknown price".