Use caps that open and close to create these fun bottle cap answer keepers. Click here to see the full post from me at FlapJack Educational Resources.
Check out these cute ladybug lids from Amanda Formaro at Crafts by Amanda. Students can count the dots on each ladybug (And Amanda has many amaaaazing recycling crafts at her site.)
I used a post from Amanda to create these funny little monster lids. We then did math and graphing with them in a lapbook. You can check out the guestblog post here at The Organized Classroom (freebie graph included).
Cindy from Love2learn2day has many great activities for recycling. Here's one of her posts on using milk jug caps to teach math.
Growing in PreK shows this great idea in a math center post that originated from Msv1st grade's blog. You'll need to scroll down to see in detail.
Here'a a math facts bottle cap activity that my students and I have so much fun with. Free labels are included in the post here.