Muliplying the Russian way

Until modern eductaional methods were introduced this century, Russian peasants used an ingenious method of long multiplication that involved knowing how to double a number, how to halve one, and nothing else beyond simple addition.

They would form two columns headed by the numbers they needed to multiply. The method works like this:

Example: To multiply 97 by 39

Step 1: Progressively halve the numbers in the left-hand column (ignoring remainders) and double those in the right-hand column. Continue this operation until the left-hand column is reduced to the number 1.

97 x	39
48 x	78
24 x	156
12 x	312
6 x	624
3 x	1248
1 x	2496

Step 2: Cross out all the even numbers in the left-hand column, along with the adjacent numbers in the right-hand column.

Step 3: Add up the remaining numbers in the right hand column to give the answer

	39
	--
	--
	--
	--
	1248
	2496
Answer	3783