The ancient Ethiopians had a way of doing multiplication where they only had to add and to multiply by twos. It is known as duplation and mediation (doubling and halving). A variation of their method is still used today in rural communities of Russia, the Arab world, and the Near East. The method involves placing each number being multiplied (multiplicand) into one of two columns. It doesn’t matter which. The left hand column is thought of as pebbles and the right hand side is though of as houses. The algorithm is to double the pebbles and take half of the houses, neglecting remainders by taking them away. The rows with an even number of houses are considered to be evil and are crossed off. The sum of the remaining pebbles is then summed.

 

6        x 9

 6                              9

 

 

It may seem a bizarre way to multiply but it is actually a very logical method. Once children have practised with one digit by one digit multiplications you can get them to try more difficult examples,

 

24 x 36

 

 

  192                      4

  384                      2

  768                      1

 

  864