Product Name: Roller Design Digital Teaching Stamp, Math Stamps Practice Tools Within 100 Supplies Educational for Preschool All Arithmetic (1 Pcs) Package Contains : It has 1* Math Teaching Rolling Stamps with ink Material : PVC Product Size: 48*44*30MM Blot: 20*4MM  Weight : 400 Additional Information: Good Quality: photosensitive process, clear stamping, Print thousands of impressions without losing the original quality, Strong ABS plastic components and housing. Interesting School Supplies: The teaching stamp set as fun as toys, makes learning fun and exciting, increase children's interest in learning ! suitable for students to practice, parent guidance, teacher teaching. Refill Pack: Roller Stamp with 1 Free refills ink, open the oil cap and drop 5-6 drops at once. Adjustable numbers, gently scrolling, and quick questions without paying a high price for math problems --Rotate and adjust the column type, you can adjust 10 different queue methods to meet all addition and subtraction numbers from 1-100 --Arrangement needs to be changed every 10 math problems to avoid duplication -- The mark is clear, dry and does not fade after printing, and ink can be added for repeated use. Parents can prepare math exercises for their children, and children can also prepare exercises for each other, learn together, and make progress together Styles: Addition/Subtraction/Multiplication/Division Kind tips: 1. Due to manual measurement, please allow a slight error. 2. Colors may be slightly different due to different monitors.