Yes there are educational learning games that will help a child learn basic things. These games should be monitored by adults, and kept to an appropriate time constraint.
One can play online educational history games for kids on the 'Kaboose' website where they have a number of games. One can also play them on 'Kids Past'.
It's mostly for kids but you can find plenty of games that are entertaining for kids as well.
The Kidz Page website provides a wide variety of educational games for kids. One can find puzzles, coloring pages, clip art, word games and picture games.
PBSkids.org/games is where you can find all sorts of games for kids of all ages that are super educational.
The best site for educational games, in my opinion, is www.freerice.com. Not only does this site provide educational games, but it also helps feed the poor with rice.
Wii and DS both offer quite a few educational video games. DS has some that are specifically for math.
show them features of the ds that might make them interested (ex. the ds's touch screen.) you could also start out by getting more educational games such as brain training games or games for learning another language.
www.thekidzpage.com give a lot of educational fun free online games for kids. I'm sure they will find it very fun and excited about how many games there are.
There is coolmath kids can learn things on that educational website
roblox is the #1 site for online educational games for kids of all ages.
Sprout, Nick Jr., and PBS have several educational games available for free online. They are age appropriate and contain no links to outside websites you wouldn't want your kids to visit.
The best computer games for kids in this age group are educational games such as star.com or Caiioo. Kids at this age are just honing in on their computer skills so less is better.