i need tax to cover Tienanmen square & summer palace how much it cost

If you just take a taxi to drive along the Chang'an Avenue to see the Tiananmen Square and after that directly to get to the summer place, the fare is around 90 to 100RMB.
But I think you can wander around the Tiananmen Square for one to hour hours, because there are some halls and palaces to be seen. After that you can take a taxi to the Summer Palace.