We reviewed skip counting this week with a Doodle Buddy activity. Students created 3 screens showing count by 2s, 5s, and 10s. Since they had a time limit I told them up front that they had to use the face stamps and the small size, thus limiting how long they spent choosing their stamps.
I asked them to stamp and label the different counting and determine how high they should go with each number. The first grade team had determined counting by 2s to 30, by 5s to 50 and by 10s to 100 would be good targets, but I ended up leaving it open-ended. Every student did count by 10s to 100 and explained that it "made sense" as well as being the amount that would fit on the screen. Most of them counted by 5s to 50. Common reasoning for that was half of 100, which they had used for 10s. The results for 2s were all over the place ranging from 20 as the highest number (because it was 10 times) to 80 (because that filled the screen).