​5 MiNUTES Recapping :

​1) Computer was not invented by a single man .

2)The invention of early counting devices led to the invention of computer .

​3) Early calculating devices are

a. Basic Counting System--> Man used his fingers and Toes to count .

b. Barter System --> Men used to exchange their goods with other

people's goods. this system is also called ["Give and Take"].

c.​Pebble counting system --> Early men used small stones called [pebbles] for counting their animals.

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Learning Objectives :-

​1) Recognize ABACUS and Napier Bones Counting System

​2) Differentiate between them

​Think for 1Minute about what is ABACUS Counting system ? In which country was invented?

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​Napier's Bones

​Was invented by John Napier

​Used for Addition, subtraction, multiplication and division.

​This device had a set of eleven rectangular rods called Bones with numbers stamped on them.

​Let's listen to the video

​Figure Out the answer from the video

​ABACUS :-

​ABACUS is one of the early counting and calculating devices .

​It was invented in China and it is still used in China, japan and Russia.

​It is made of a wooden frame with small balls threaded on the rods called beads .

​It was the first "Manual Calculating device".

​What is Napier's Bones Counting System ?

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​1. Which device had a set of 11 rectangular rods called "bones" with numbers stamped on them ?

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​2. Which was the first Manual calculating device ?

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