Thursday, 2 July 2009

Oldest method of multiplication

During olden days, people knew multiplication table 2 only and with that they were doing multiplications. Old multiplication method used the following steps

Step 1: Divide the left side number by 2, if you get remainder, omit it. For example 3/2=>1.
Step 2: Multiply right side number by 2.
Step 3: Cancel the right side number, if opposite left side number is even.
Step 4: Add the remaining numbers on the right side; you will end up with the answer.
Example:
23x42

L R
23 - 42
11 - 84
5 - 168
2 - 336(cancelled since left side number is even)
1 - 672
Answer: 42+84+168+672=966(omitting 336 since 2 is an even number)

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