t-1334-1337 RUSSIAN PEASANT MULTIPLICATION JUNIORRCLE 11S2011 Russian Peasant Multiplication is a similar procedure to Egyptian Multiplication. Suppose that you have to multiply two numbers (e-g., 21 and 18). The basic operation for them was multiplying or dividing a number by 2. They reduced all other multipli- cation problems to it. Here is how they would start multiplying 21 by 18 (in modern notation): 21 18 21 18 10 36 5 72 2 144 1 288 Here is what to do to complete the multilpication (1) In the first column, take the first number and continue dividing it by 2 until we reach 1. If there is a remainder, drop it. (Eg. 21/2 10 with remainder 1, (3) After that, we choose the rows with odd numbers in the first column. (in our Finally, all there is to do at this point is to add the marked numbers in the second so we just write 10.) Keep dividing until we end up at 1. (2) In the second column, we keep doubling the second number (in this case, 18). example, we chose the first, third, fifth and seventh row) column: Thus, the result of the multiplication is 378. Coppright @2008-2011 Olps Radko Los Angeles Math CieleUCLA Department of Mathematies