Alien Math is a great little math app and very basic for preschoolers through 1st graders, or anyone who struggles with speed math. The free version that I reviewed is ad supported, but definitely gives you the feel for the game. The “prizes” are aliens that you can move around the screen. The aliens are cute, but not really a great incentive past the first few times you play with them.
This educational app and many others are designed / developed by Brain Counts are all pretty good apps for kids. However, the one consistent complaint is that some of the ads shown on these kids apps are not child-friendly, such as dating sites and gambling. I am not sure how much control there is available over the ads, but this is really a big turn off from the free version.
Also, several of the apps are similar except for different theme, such as a math app like the one reviewed, but with animals. It is definitely not necessary to download them all, but it is nice to have a choice based on your kids likes. My other comment is that these apps could and should be universal apps, if the iPad version is dramatically different that’s fine, but these aren’t.
Bottom line: check out the free version, then upgrade if you like it. It’s worth it!