Jim runs away from miss Watson because He finds out that she is planning to sell him for $800.00.
Explanation:
This event happens in Chapter 8 of "The Adventures of Huckleberry Finn" by Mark Twain, Jim during an unfortunate moment had overheard Miss Watson planning to sell him to a slave trader for $800, since he did not want to be taken away and sold and send to New Orleans, he comes to think that running away is the best option.
Jim<span> ran </span>away<span> because </span>Miss Watson<span> was going to sell him down South. Huck </span>runs away<span> from his abusive father, and soon </span>runs<span> into an escaped slave. While he lived with </span>Miss Watson<span>, Huck got to know </span>Jim<span> and appreciate him. When </span>Jim<span> told Huck that he had </span>run<span> off, Huck was surprised, but he promised not to tell anyone.</span>