I would go with concept instead of notion. We tend to use notion in place of the word opinion, and when we say kids don't have the same notion of money, it's almost implying that they know as much as adults, but simply disagree with how they view money. I like the word concept because it ties more into an understanding of something, or a realization. In the case of kids, they don't have the same concept of money because they simply don't understand it as much as we do. Yes, IN works just fine. In is considered a preposition, let me copy paste a quick and easy to remember lesson regarding a certain type of preposition. Prepositions of Time: at, on , and in We use at to designate specific times. The train is due at 12:15 p.m. We use on to designate days and dates. My brother is coming on Monday. We're having a party on the Fourth of July. We use in for nonspecific times during a day, a month, a season, or a year. She likes to jog in the morning. It's too cold in winter to run outside. He started the job in 1971. He's going to quit in August. Prepositions of Place: at, on , and in We use at for specific addresses. Grammar English lives at 55 Boretz Road in Durham. We use on to designate names of streets, avenues, etc. Her house is on Boretz Road. And we use in for the names of land-areas (towns, counties, states, countries, and continents). She lives in Durham. Durham is in Windham County. Windham County is in Connecticut. grammar.ccc.commnet.edu/grammar/prepositions.htm

Hello alc24, I am glad to help. I was born in Australia but moved here when I was young, so I've lived in California all of my life. I am paid to be an English tutor at the college that I go to, and I decided to start helping people online here as well.