Napier’s bones consist of 10 rods or blocks that have multiples of different digits on each side. When multiplying a number, for example, 598, use the rods with those particular digits on the top. Place these rods next to one another with a strip on the far right side with numbers 1 through 9. If you are multiplying 598 by, for example, 27, then examine rows 2 and 7 of the rods with 5, 9, and 8.  Start with row 2 and write down each number you get by adding the digits in the parallelograms. Do this again with 7, and then add these two numbers to get the product of 598 x 27.