The CCSS and our new Texas TEKS require that students count to 120, rather than 100. I’ve been waiting for the teacher supply companies to catch up and create a 120 pocket chart, and it looks like they finally have. Here’s a link to one of them on Amazon. Mine is on the way!
Some people ask why 120 instead of 100. I think I can illustrate with an example from working with my 2nd graders today. We were exploring 10s on a hundred grid (think blank hundred chart). I quickly showed them the blank chart, turned it facedown, and asked how many squares they thought were in one row. I got responses of 10, 5, 10, and 11. I turned the blank chart back over and we verified each row had 10 squares. Then I asked how many rows they thought were on the chart, once again hiding the chart. All four students responded 10. We turned it back over and verified our estimate. Then I asked how many squares they thought were on the chart. I got responses of 100, 1000, 1000, and 100. I turned it back over and we talked about what the addition sentence would look like (10 + 10 + 10 + 10 + 10 + 10 + 10 + 10 + 10 + 10 = ____) to find the total number of squares. Then we skip counted by 10s to verify that 10 tens would equal 100. On a whim (a lot of my teaching is on a whim…), I ran my finger along the imaginary next row and asked what would come next counting by tens. I got very puzzled looks and responses of 101, 1000. 111, and shrugged shoulders. Okay…
I decided to proceed with an equation. I said, “Well, if we had one more row that would be ten more, right?” Yes. “Okay, so it would be 100 + 10.” (I wrote this on my easel). Now I saw a few lightbulbs and got a chorus of 110! So what would come next? Still a group of very unsure faces. “Okay, so it would be 110 + 10, right?” and I wrote down the equation 110 + 10 = ___. Oh! 120! Then we went back to the hundred frame and skip counted by 10s from 10 to 120. I pointed out that we start skip counting by saying 10, 20, and after we reach 100, we see that repeat when we count 110, 120. They ate it up–I should have had a magician’s cape on!
Bottom line, students need to see that the patterns continue after 100. If you want to extend your current pocket chart (or the one you’re going to buy!) on out to 1000, check out this blog post for a free set of cards that will fit your pocket chart.