One thing that I do every year, is read the story One Hundred Hungry Ants by Elinor J Pinczes and Bonnie MacKain. This story is great for visualizing ways of grouping 100 objects. We usually try to do some of the same grouping in class, but we quickly run out of people and have to come up with alternatives. The stuffies come out and so do blocks, or other objects around the classroom. I just came across this post on Classroom Freebies that has activities for 100 ants that will tie in nicely with the ones I do. 100 Days With Ants from Diane at TeachWithMe.com
Money is another popular thing to sort and count, so I get out all the school money tubs and we do activities using the coins and the paper money.
This year I also thought about doing 100 Random Acts of Kindness. If we started now, it is possible to reach 100 in time. We would have to do about 5 a day to make it in time.
What are you doing for Hundreds Day?