MaterialThis analog display wall clock made of high quality Acrylic material with white letters and numbers, great for classrooms or the office Special Design Black clock face is made to look like a chalkboard with each math equation painted to look like white chalk.Instead of traditional numbers, this wall clock has a different equation at each demarcation. Funny MathematicalAs the clock ticks, the hands move around the dial indicating 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 funny and challenging brain exercise. Fashion DecorationA very fashion decorations for the wall, especially for classroom, office and study room as well as an ideal gift for your friends or their kids ApplicationIdeal for the budding mathematics student or for anyone who wants something a little different in a clock.For Classroom,Study room,Living Room,Kids Girls Bedroom,Office. When the watch ticks, the hands move around the dial and indicate the time displayed by another mathematical problem for each hour. This unique wall clock is a fun and challenging brain exercise. The black dial is designed to look like a blackboard, with each mathematical equation looks like white chalk. Instead of traditional numbers, this wall clock has a different equation for every border. Material: Acrylic. Colour: black. Power supply: 1 x AA battery (not included) Product diameter: Approx. 30 cm. Package weight: Approx. 341 hours