The only homework I require is 60 min. of IXL time a week. They know to log on to IXL, click on "recommendations", and then choose a math related skill to work on. This caters more to each individual child and what they need to work on. Kids have PLENTY of time to work on their minutes at school on IXL days, but they are expected to work on it at home as well. They are certainly welcome to work on it for more than 60 min. a week, but I have found this amount of time appropiate in the past. Let me know if you have any questions!
*Some short weeks will not require 60 min.