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Peasant multiplication

Peasant multiplication is an old algorithm for multiplication. It requires no use of a multiplication table; however, it requires that the user be able to divide by 2. The user must also know how to add.

  • Write the two numbers (A and B) you wish to multiply, each at the head of a column.
  • Starting with A, divide by 2 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-columnB-columnAdd this
278282
13164164
6328
3656656
113121312
Result: 2214



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