Copper-plated Nabil chip handheld computer

[Copper-plated Naber chip handheld computer]

Copper-plated Naber chip handheld computer, made by the Qing Palace Building Office, was 58 cm long, 12.5 cm wide, and 4.5 cm high during the Kangxi period of the Qing Dynasty. The old collection of the Qing Palace
The computer is rectangular. There are 10 rectangular holes on the computer and 10 tooth chips inside, representing 10 digits. Inside each rectangular hole is a rotatable cylinder, on which is carved a vertical ivory Nabil numerator, and the numbers on the numerator are expressed in Arabic characters. There is a rotatable knob beside each opening. When calculating, move the knob, and use the rotation of the gear to calculate the addition, subtraction, multiplication and division by Nabil calculation method.