3 days Shanghai, then Beijing for 4 person + 6yrs old child

Hello, according to your situation, you are advised to purchase the Three-day Travel Pass. It is sold CNY 45 and could be purchased at any ticket booths set at these subway stations. With this pass, you can take all the subway lines without limit in 72 hours after the first use. In addition, this pass is not required to be returned after use so passenger could keep it as a souvenir.