Product Description: Quantity: 1 piece Color: Black Product Dimensions: 30 x 30 x 4 cm Material: acrylic Requires one AA battery (not included) Excellent gift idea: offer one of these clocks wall clocks to a math teacher, engineer, mathematician or anyone who loves numbers The clock is a traditional wall clock with a three hand movement but with an important twist - its hours are marked by simple mathematical equations. To tell the time, you solve the answer A unique gift idea, the math clock makes a fun gift for a math teacher to hang in their classroom. It's also the perfect desk clock for an engineer, accountant, mathematician, or anyone else who works with numbers. For home use, the clock will add a geek chic finishing touch to any room.