# Famous Mathematicians: Using Subtraction To Determine How Long They Lived. (classes 9-21 thru 9-25)

Mr. Kramer's favorite ten mathematicans:  how long did they live?

Mathletes subtracted their year at birth from their year at death to determine the number of years of their lives.  In the case of mathematicians that lived in the time before Christ, we subtracted the year at death from the year of birth.

See the attached file with the worksheets for the ten mathematicians on Mr. Kramer's chairs: Plato, Archimedes, Gauss, Euclid, Euler, Fermat, Fibonacci, Pascal, Einstein, and DaVinci.  This file includes a paragraph about each man and his contribution to mathematics.

After the Mathletes determined the ages of each mathematician at death, they added their ages together and then divided the sum (679) by the number of mathematicians (ten).  They determined that the average age of these men was about 68. Since the life span of humans was only as high as 34 until the mid to late 20th century, the Mathletes determined that these mathematicians outlived their life expectancy by about double on the average.

So therefore, since Mr. Kramer's lifespan is currently at around 78, he should live until he is 156. Horray for mathematicians.

Use subtraction without borrowing to determine the life ages of another 15 famous mathematicians (see the highlighted names on the attached word document).  Use subtraction with borrowing to determine the life ages of another 56 famous mathematicians (see the un-highlighted names on the attached word document).

Subtraction without borrowing (highlighted on the word document) is most appropriate for 1st graders.

Mathlete Files: 10 Famous Mathematicians: Subtraction to determine age
Mathlete Files: 71 More Famous Mathematicians: Subtractions with and without borrowing.
Mathlete Files: subtraction_intro.pdf