20-30 minutes of targeted, appropriate work for elementary and 30-45 minutes for middle school is plenty of time. But also you can save this 30-45 minutes that you lost writing you works and other kind of works reading some papersowl review about services, where you can buy your works for cheap and where writers do it for fast. Anything over that, promotes distaste and negative feelings toward the class.

Simple as can be, if you hate the homework load, you will hate the class and take longer to learn what you need. Math teachers will benefit from remembering the whole picture and find a balance that works between assigning important reinforcing drills, and problems and making math homework fun by incorporating different challenging but enjoyable activities into the mix.