Jem means that its not right that an innocent man gets railroaded by racism.
When Jem says "it ain't right," he is expressing his belief that something is unjust, unfair, or morally wrong. This shows his sense of empathy, moral compass, and desire for justice.
The outcome of the case was unfair.
When Calpurnia says Jem has the "look arounds," she means he's behaving suspiciously or behaving in a way that suggests he's up to something. It implies that Jem is acting in a sneaky or curious manner.
When Miss Maudie says that Jem gets more like Jack Finch every day, she is implying that Jem is becoming more mature, responsible, and thoughtful - traits that are characteristic of his Uncle Jack. It suggests that Jem is growing into a respectful and wise young man, similar to his uncle.
Jem's response "In a pig's ear you did" is slang that means disbelief or skepticism, similar to saying "I don't believe you" in a playful or sarcastic way. Jem doesn't think that Dill actually helped engineer the train; he is expressing doubt about Dill's claim.
Atticus says he will never worry about Jem because he believes that Jem is maturing and developing a strong sense of morality and integrity under his guidance. Atticus trusts that Jem will make the right decisions based on the morals and values he has instilled in him.
Jem believes that the difference in background is caused by some people being born into good families and others being born into not so good families. He recognizes that not everyone has the same opportunities and privileges in life.
Jem says he lost his pants playing strip poker by the fish pond with dill.
scout says jem is 4 years my senior.. hes four years older
Jem says that the Indians heads are real old nineteen- hundred he said.
When Scout asks Jem if their raid on the Radley house was all right, Jem replies, “No, it wasn’t all right. The way I’d feel if I did something wrong would be just the same as when I’d done wrong.” This shows Jem acknowledging that their actions were wrong.
Boo Radley saves Jem and Scout in Chapter 29 of "To Kill a Mockingbird" when he emerges from his house to defend the children from Bob Ewell's attack. Boo intervenes and ultimately saves Jem and Scout from harm.
Its when Jem builds the snowman and replicates Mr Avery. Then Atticus says that to him. I think its because Jem has showed signs in the past that he wants to do what Atticus does; law, not sure about engineer and portrait painter as Jem has shown that he is artistic when he builds the snowman. Actually I think he says engineer as its something completely different from the other 2 jobs he mentions, which exaggerates the diversity of Jem's future.
Jem cries because everything good and right has been shot down by the jury.