I don't have a definite count for you. The number could change as new ones are published or some are no longer available. You could try searching on comic-related websites or asking in comic forums to get a better idea.
It's hard to give an exact number. New babysitters graphic novels might be coming out all the time, and older ones might go out of print. You might want to check with specialized comic stores or online databases for the most accurate count.
Chapter 424, "He Must Be Very Strong", is the clearest early answer because it turns Ji Yanbai's situation into a concrete plot event. It opens with Shh!" Jiang Yan, who was leading the group, turned around and made a... and closes on Isn't this just exploiting a loophole?!.
Chapter 518, "Calculator: 438", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. Early on, I won't eliminate you." Jiang Li's statement came as a shock.. By the end, Meanwhile, unbeknownst to anyone, he had already quietly eliminated....
Chapter 659, "Bodyguard Agreement", is the clearest early answer because a shaky connection becomes usable in the plot. The chapter gives readers a real answer by opening on Besides, how easy is it to get into the Gu Family? and ending on The woman who had defeated him and taken all his hopes..
Chapter 498, "How can someone be so ugly?!", is the clearest early answer because it turns Ren Yue's situation into a concrete plot event.
Chapter 374, "From Now On, Jiang Li Calls the Shots in Golden Sand!", is the clearest early answer because it turns Jin Siyue's situation into a concrete plot event. It opens with Jiang Li's bold behavior infuriated Jin Siyue, but it also succeeded...
Chapter 738, "Here to Fight!", is the clearest early answer because the buildup finally cashes out in a real clash. The chapter turns that into something concrete by moving from Feeling that something was amiss, he immediately called Jiang Li.
Chapter 444, "Wait and See", is the clearest early answer because it turns Shang Shuyue's situation into a concrete plot event. It opens with Carrying a backpack, Yu Li walked for over ten minutes but ultimately...
Chapter 719, "Borrowing Their Luck", is the clearest early answer because it turns Ye Chu's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Chang Rong: "Hmph, it has nothing to do with me anyway, since no one...
Chapter 692, "My Ideal Type is Assistant He", is the clearest early answer because it turns Do's situation into a concrete plot event. The chapter turns that into something concrete by moving from Zhao Lang's gaze stayed fixed ahead as he gripped the steering wheel...
Chapter 569, "Watch How My Sister Torments You!", is the clearest early answer because it turns Ai Xiaochun's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Due to the unequal number of members on Team J and Team Q, the system...