Family left $200 on counter when I’m watering their plants for a week, should I ask if it’s for me?

I babysit for this family who is pretty wealthy and they are on vacation so I’m watering their plants. Usually I make $20-$30/hour and they venmo me. When I went to their house today there was $200 on the counter. I don’t know if I should reach out and ask if it’s mine or wait to see if they say something. I don’t think they would just leave money like that on the counter. This is a stupid problem but I’m confused.