MATERIAL - This analog display wall clock made of acrylic material with white letters and numbers, ideal for classrooms or office. Special Design - The black face of the clock was designed to look like a blackboard, with each math equation painted to look like white chalk. Instead of the traditional numbers, this wall clock has a different equation for each boundary. Funny Mathematical - The pointer moves around the watch face to indicate the time of day through a different math problem for each hour. A unique and creative way to keep track of time, this wall clock is a fun and stimulating brain exercise. If you can read this watch, you are definitely a math geek. Each lesson is marked by a simple math problem. Solve it and solve the time riddle. Great for budding math students or anyone who wants something different in a watch. Application - Great for the aspiring math student or anyone who wants something different in a watch. For classroom, office, living room, nanny room, office. Product Note: As for the battery, the battery is not included, please use the carbon-zinc battery, please do not use the rechargeable battery or other batteries, due to the high output current of these batteries, the clock accuracy may be affected.Specifications: Material: Acrylic Black color Shape: round Size: 30 x 30 or 11.8 x 11.8 inch Power supply: 1 AA battery (not included) Unique appearance and good performance, fashionable look and accurate time display. The clock measures 11.8 inches in diameter, it is easy to see from a distance. A unique and creative way to keep track of time, this wall clock is a fun and stimulating brain exercise. Any lesson marked by a simple math equation can overwhelm your fear just by solving a few simple math problems with each corresponding lesson. Great Gift Idea Give one of these wall clocks to a math teacher, engineer, mathematician, or anyone who loves straight numbers. A very trendy decoration for the wall, especially for the classroom, office and study and an ideal gift for your friends or their children. Package includes: 1 x math wall clock Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.