ABACUS

 ABACUS:

• It is believed that abacus was invented by Chinese or Egyptian about 500 years ago. Chinese called it 'suan pan' which means counting device.

• Abacus consists of a frame mounted with rods along which beads or balls which are moved for calculation.

• Abacus is used for making calculations like to find sums and differences.

  

• Its features are as follows:

         a) This can in turn help to solve equations involving counting numbers.

         b) Abacus is a portable device.

         c) It is built out of wood & beads.

source:wikipedia.org