The third generation of computers used ____________.

In 1694, Leibnitz  improved _____________ machine 

First generation computers were used in __________ period.

In _________ generation of computers used vacuum tubes, this made them very bulky and they generated a lot of heat.

In _________, John Napier invented a calculating device called Napier's Bones.

Abacus was invented around ___________

In ______, Blaise Pascal invented an adding machine called Pascaline.

The fifth generation computer device is based on _________.

A modern computer has.