For every 10 books your child reads, they will get a bubblegum on their bubblegum chart.
For every 100 books (or 10 bubblegums) your child reads, he/she will be inducted into the 100 book club (there is also 200, 300, 400, and 500 book club). The 100 book club is the goal, but your child can also strive towards the bigger goals.