Slide Rule:

• Invented by William Oughtred in 1622.
• Is based on Napier's ideas about logarithms./li>
• Used primarily for :

1. multiplication
2. division
3. roots
4. logarithms
5. Trigonometry

Pascaline:

• Invented by Blaise Pascal in 1642.
• It was its limitation to addition and subtraction.
• It is too expensive.

Stepped Reckoner:

• Invented by Gottfried Wilhelm Leibniz in 1672.
• .The machine that can add, subtract, multiply and divide automatically.

Arithmometer:

• A mechanical calculator invented by Thomas de Colmar in 1820.
• The first reliable, useful and commercially successful calculating machine.
• The machine could perform the four basic mathematic functions.
• The first mass-produced