Still manually writing arithmetic questions for your child? Roll gently smart math roller and 100s of math problems will appear immediately. Cute and practical. Advantages: Addition, subtraction and multiplication questions to choose from. Easy roller design with a gear to adjust question sequence. Ink comes with the box, which can be reused again! Efficient and quickly gives you 100s of practice questions, no smudge, no fading! Rotate to adjust 10 different question sequence. Small and exquisite, easy to carry. Specification: - Weight: 120g - Material: Plastic - Choices: Addition, Subtraction and Multiplication - Colors: Blue and Pink - Size: 4.4*3*4.8cm/1.7*1.2*1.9in - Package Contents: 1x Arithmetic Artifact (Contains seal ink)