Thank you for your request.
In this case, I can suggest our Swiss travel pass. This is available for 4 days. You have all the information and the possibility to buy here.
The Swiss travel Pass has a great offer for children. See the information at the bottom of the page.
Alternatively, you can travel with the Saver Day Pass, as suggested by @RolandP. For children there is the Day Pass Children.
If you have any questions, we are here for you. Have a nice weekend.