Amy has some money in her checking account. If she writes a check for $40.50, her checking account will be overdrawn by $21.50. Find how much money is Amy's checking account now.

Okay. So basically, Amy's account will be overdrawn by $21.50 if she makes that $40.50 check. So, in this case, we would have to subtract the check price with the overdrawn price to see how much she has in her bank account now. When you do 40.50 - 21.50, you get 19 is the difference. Amy has $19 in her checking account right now.