[Early Teaching Exercises]This number teaching stamp roll consists of multiplication, addition, subtraction and exercises. Gently scroll, you can print problems efficiently and quickly, which is convenient for children to homework. [Random Exercises]Random exercises can develop children's logical calculation and comprehensive mathematics . Numbers from 1-100, exercises include addition, subtraction, multiplication and . [Clear Printing]This digital teaching stamp roller is equipped with high-quality ink, which is suitable for most and is fade-resistant. It is recommended to print on the back of discarded documents, which saves paper and is environmentally friendly. [Reusable Teaching Stamp]The digital teaching stamp roller is easy to refill with ink, and the transparent storage box prevents ink from spilling. When the ink runs out, you can add 5-8 of ink to the side of the roller stamp, wait a few minutes for the ink to continuing to use. [Perfect Gift ]The digital teaching stamp roller is small and exquisite, which can be carried around and put into a pencil case. This is a unique gift to improve skills and improve concentration. Color: As Shown Material: PP Package Contents: 4 x Practice Chapter 4 x printing ink Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.