You don’t mention how old your kids are or what math facts you are wanting them to learn. We have done xtramath.org in the past, great site.
I would like to say though that Times Tales has been the best thing thus far for learning multiplication math facts. Both my kids used this method and neither of them have ever had a problem with remembering their facts.
We love Fred. We use Teaching Textbook for days a week, but on that 5th day, we do Fred as a family and we do 5-8 Chapters depending on time. I do have kids write down their own answers and then we discuss. It has worked out great. Best of Luck.