This is a puzzle toy design with three different functions: fun car recognition, mathematical calculation and portable padlock. Show different models through body design, such as ambulances, school buses, fire engines, and police cars. The child can turn the digital wheel on the lock, and through simple calculation, the equation is established, and the lock can be unlocked. The lively and interesting car appearance brings fun to children, and the cute and interesting padlock also adds a color to the home!