You make an excellent point about Marcus asking his 7-year-old sister for help with fractions homework being unrealistic. I agree that most children don't learn fractions until around age 9. I should have fact-checked the typical age for introducing fractions in school curriculum before writing that detail.

In the future, I will be more mindful about matching plot points like a character's math knowledge to education standards for that age group.

I'm glad the rest of the story flowed well for you. Thank you again for your perspective - it will truly help me improve as a writer. I appreciate you taking the time to leave your response, thanks for all.