This strategy game is fun for all ages. It’s a classic, from the imaginative mind of H. E. Dudeney.
“The Ten Cards” is an excerpt from Math You Can Play Combo: Number Games for Young Learners, which is available as an ebook at my publisher’s store (where you get all formats for one low price, and I earn higher no-middleman royalties) or through other online retailers, or by special request through your local library. Read more about my playful math books here.
The Math Game Monday posts will be available for one week only. If you missed this one, explore the links in the sidebar. There are more than forty free games scattered around the blog. Have fun playing math with your kids!
Denise Gaskins' Let's Play Math 
I would turn over the 9 and 8 insuring I would turn over the last card.
The 9 and 8 are not next to each other, so you can’t turn them both down on the same turn. But I think you have the right idea, if you pick a different pair of cards. 🙂