Jayden made $1,365.76 by baby-sit this month and $987.63 by baby-sitting last month.How much more money did Jayden make this month and last month

what, no calculator?

Your question is poorly worded. If you meant to ask

How much money did Jayden make this month and last month?
1365.76+987.63 = 2353.39

If, on the other hand, you meant to ask
How much more money did Jayden make this month than last month?
1365.76-987.63 = 378.13

Math isn't like English. You can't always rely on someone else to figure out what you mean.