500
A good estimate to the following:
Abby wants to buy a book for $5.25 and a book for $4.85. She wants to pay with a $10 bill. Use estimation to decide if this is reasonable. The explanation of what place value to round for an estimate that is useful in this situation.
What is more than $10? When estimating money and time it is best to be conservative. If you let the $5 rest, round the $4 to a $5, you still have to consider the change. If you round the $0.25 to $0.30 and round $0.85 to $0.90, you will get $1.10 added to $9.00, it is $10.10 and so $10 is not enought.