I believe the answer to this is "If they babysit for 5 hours, Jayna will earn more" because Hannah charages 7$ an hour and Jayna charges 10$ an hour so Jayna will have more money than Hannah in five hours.
Lets say... 7 divided by 21. ok? So... Just take 7, (usually the smaller number, but not in all cases.) and then multiply it by 1. 2. 3. So lets see. 7x1=7 so thats not it. 7x2 is 14 so thats not it. And you want to keep doing that until you get the other number. 7x3 is 21!!! That is the correct number so if you were doing long division like this
___3______ <--- the answer would be there.
7|21
When you have powers of 10, the number is always 1 followed by how ever many zeros. So, in this case, 10 to the 4th power is 1 followed by 4 zeros, which is 10,000
