I mentioned back at the Preschool's Out for a Week post that I got these but hadn't used them. Well we used them, and they rock! My son already loves his Scout animal (the one that sings their name in songs and such), so it was easy for him to find interest in the cards. Both sets (sequencing and opposite mach up) are awesome for building preschool cognition. They say ages 4 and up, but he's barely 3 and did wonderfully. This set is much cheaper than the Melissa and Doug sequencing blocks I've been coveting. Here's one way we used the cards, with pipe cleaners to "draw lines" to the matches.