Amazing Number Chart The Amazing Number Chart is appropriate for kids ages 5 – 10. It is a free online application for teachers, parents, and students, that reinforces counting, skip-counting, multiples, and number sense. Perfect for grades K-4, The Amazing Number Chart allows teachers to build, save, and deploy to students custom-made number charts that must be filled-in ONLINE according to their rules. No registration required! Simply build your number chart, click “save” and the system gives you a code to give to your students so they can complete your number chart.