There are 3 versions of this letter. You can send them home at various times during the year based on what your counting benchmarks are. I have included one for up to 40, one for up to 64 and one for up to 100. These are the benchmarks my school uses for fall, winter and spring.
This also helps you as a teacher keep track of what they student knows and builds the communication between home and school. Plus, having a letter come from their own child is priceless! Who wouldn't want to help the child who asks for it!!