Practice with numbers and number bonds up to 20 on these flexible plastic double-sided dry-erase boards. One side features a blank ten frame and a number bond while the reverse includes two blank ten frames and a number bond. Use with low-odor dry-erase markers (not included). Measures 9" x 12". Set of 10. Recommended Grade(s):K-2 Practice with numbers and number bonds up to 20 on these flexible plastic double-sided dry-erase boards. One side features a blank ten frame and a number bond while the reverse includes two blank ten frames and a number bond. Use with low-odor dry-erase markers (not included). Measures 9" x 12". Set of 10.