Features: 1.Digital Teaching Stamp Roller: New addition and subtraction mathematical stamp design is unique, open the lid rolling can set questions, more convenient and quick to use. 2.Math Skills Development: Rotate and adjust column types to adjust 100 different combinations. Develop children& 39;s logical calculation ability. There are four kinds of stamps for you to choose from. 3.Reusable: The drum digital teaching stamp is compact, easy to carry and can be reused by adding ink. After printing, the handwriting is clear, dry and colorless. 4.The Gift of Learning and Education: This is a great gift that parents can quickly prepare their children for when they need to practice math problems. Exercise children& 39;s arithmetic ability. 5.After-sales Service: If you have any problem, please contact us immediately, we will help you solve it as soon as possible. Specifications: Product Name:Math Teaching Roller Stamp Product Size: 4.5*3*4.8cm Suit for:Students,Teacher Notice: 1.Actual color may be slightly different from the image due to light effect. 2.Please allow 1-3cm deviation due to manual measurement. 1 * Math Teaching Roller Stamp 1 * Stamp-pad Ink 1 * Storage Box