The term computing means using logical and mathematical methods to calculate or process data. Some devices were used to do this even before the invention of the computer.

Examples of such devices include; Abacus, Slide Rule, Napier’s Bones, Percaline, Stepped Reckoner.

## ABACUS

(made by sir Abacus) :It was used then to perform addition, subtraction, division and multiplication. It can also be used to find square –roots and cube-roots of numbers.

## SLIDE RULE:

It was developed by WILLIAM OUGHTRED in the year 1622. It was used to calculate division, multiplication and special functions (e.g. logarithms and roots) it cannot be used for addition and subtraction.

## NAPIER’S BONE:

It was invented by JOHN NAPIER in the year 1617. It was a simple computing device for mathematical operations (such as products and quotient of numbers)

## PASCAL’S CALCULATOR (PASCALINE):

It was developed by BLAISE PASCAL in the year 1642 it was used to carryout or make simple calculations. It adds, subtracts divide and multiply numbers.

## LEIBNITZ MULTIPLIER:

This was invented by GOLTFIED LEIBNITZ (A German Scientist). It was used for addition, subtraction, division and multiplication. It is otherwise known as the STEPPED RECKONER

## EVALUATION:

- Define a computing.
- List three computing devices that belong to the 19
^{th}Century Period.*[WASSCE 2014_CST_Paper 2_Q1b(i)]* - State the uses of the following devices;

[a] Abacus [b] Napier’s Bones