Rapid Recall is what finally worked for dd13. Now, she will simply play a game or complete a timed test on occasion to stay sharp, but she’s got the facts down. Ds10 used RR too for +-x and does a variety of things periodically to stay sharp. He could have learned them any method, but used RR bc we had it. DD6 is just starting and likes the Addition Wrap Ups.
Currently my favorite is Math Fact Master and Timed Test for the ipad. We were using xtra math, but it frustrates the kids if they accidentally touch a wrong key and can’t fix it. These two new ones I downloaded this week don’t have that problem.