2. John Napier: Born 1550- Died 1617 Lived in Edinburgh Scotland during time of Protestantism Came from a wealthy family/background. Man of many talents, decent values and high intelligence (attended University of St. Andrews at the age of 13). Spent his time studying mathematics, and developing new tools and formulas to make the process of calculation easier. Napier's free time led to invention of Napier’s Rods, type of counting system However most famous for his publication of a book of Logs

3. Napier’s Rod’s, a.k.a. Napier’s Bones, is a type of abacus (counting frame) that simplified finding multiplication equations In addition, rods could be used to find division and square roots

4. To use Napier's rods,you need ten strips of paper each divided into 9 parts, one for each of the first 9 multiples of the number at the top of strip as shown below

5. We can use Napier’s Rods to multiply any two numbers Lets start simple…  E.g Take the equation 75 x 3 Place the multiplier, the '7' and the '5' bone side by side (for 75) as shown to the right. To calculate, sum the numbers along the slanted diagonals of the combined bones using the row applying to the multiplier For the two bones, when reading from right to left there are three diagonals which represent units, tens and hundreds when the multiplier is three 5 represents 5 units, the 1+1=2 represents 2 tens, and the 2 represents 2 hundreds. Adding 5 units, 2 tens and 2 hundreds gives 225. 75 X 3 = 225

6. Napier intended for his homemade calculator to solve BIGGER multiplication problems…  E.g. Take the equation 84 x 24 place the multiplier and the bones '8' and '3' bones, for 83, side by side as shown to the right To find the product first multiply by 4 and then multiply by 20 add just as you would for long multiplication to find the answer. Final answer: 1992

7. Okay lets get a little more complicated: 7 x 46785399 Once again, to solve multiply number by 7 then combined diagonal bones through addition Final answer: 327,497,793

8. Last example: 46785399 x 96431 Top number should be the bigger number multiplied by the smaller number on the side. Add entire sum Make sure to distinguish unit, tens, hundreds, etc. digits. Final answer: 4,511,562,810,969

10. The End