Write the two numbers (A and B) you wish to multiply, each at the head of a column.
Starting with A, divide by 2, discarding any fractions, until there is nothing left to divide. Write the series of results under A.
Starting with B, keep doubling until you have doubled it as many times as you divided the first number. Write the series of results under B.
Add up all the numbers in the B-column that are next to an odd number in the A-column. This gives you the result.
Example: 27 times 82
A-column
B-column
Add this
27
82
82
13
164
164
6
328
3
656
656
1
1312
1312
Result: 2214
The method works because multiplication is distributive, so:
This method was known to ancient Egyptians as mediation and duplation, where mediation means halving one number and duplation means doubling the other number. It is still used by peasants in some areas, such as Russia.
The technique of Ancient Egyptianmultiplication rests on the decomposition of one of the multiplicands (generally the larger) into a sum of powers of two and the creation of a table of doublings of the second multiplicand.
The earliest known indication of Egyptianmultiplication, in the form of the Ishango bone, was discovered along the headwaters of the Nile River (located on the northeastern edge of the Congo), dating to 20,000 BC.
The ancient Egyptians had laid out tables of a great number of powers of two so as not to be obliged to recalculate them each time.
EgyptianMultiplication could be used in a basic skills mathematics, prealgebra or algebra course to reinforce or introduce the concept of multiplication of whole numbers.
Egyptian civilization, one of the great ancient civilizations, included methods of flood control, irrigation and marsh drainage as well as a centralized government, a calendar, and a standard system of weights and measures.
Egyptians used a hieroglyphic system for numbers in which each character was a picture of an object which in turn represented a number.
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