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- Was 1 Ever Considered to Be a Prime Number? [02/29/2004]
I learned that a prime number was one divisible by only itself and 1,
but my 4th grader says that per her book a prime requires 2 different
factors. I note your Greek reference for 1 not being prime, which
would indicate that I'm wrong and there was no change in definition.
However, Ray's New Higher Arithmetic (1880) states, "A prime number is
one that can be exactly divided by no other whole number but itself
and 1, as 1, 2, 3, 5, 7, 11, etc." Can you tell me when this change
happened and why?
- Was Mathematics Invented or Discovered? [5/17/1995]
Was mathematics invented or discovered? Seems like mathematicians ponder
and invent, and yet, the book of nature...
- The Welsh Vigesimal Number System [02/17/2003]
What can you tell me about the Welsh version of the Vigesimal Number
- What If There Was No Zero? [10/21/2003]
Why did it take so long to discover zero? Why did early civilizations
not need zero? How would math as we know it be different if there was
- What is a Sign? [04/21/2003]
Can you do anything in math without signs?
- What is Menelaus' Theorem? [11/15/1998]
Proof of Menelaus' Theorem, and discussion of its converse and Desargues'
- What was Fermat's Last Theorem? [07/23/1997]
I wonder if you might take the time to explain Fermat's Last Theorem. I
am an undergraduate in mathematics, so an easy answer would be perfect.
- When Do We Need to Know Roman Numerals? [08/26/2003]
I have a student who does not see how learning Roman numerals will
benefit her. What advice can you give her to make this learning
experience more relevant to her life and needs?
- Where did Fahrenheit and Celsius Come From? [07/26/1997]
How did scientists figure out the relation between two numbers that mean
the same thing, e.g. 0 deg C and 32 deg F?
- Where did Pi come from? [12/2/1994]
We are an adult high school and we were wondering if you could answer our
question. Where did the word pi come from, and how did someone determine
it was equal to 3.14?
- Where does pi come from? [1/13/1995]
I was wondering how exactly the math notation pi was derived, and whoever
derived it, why did he make up that symbol for pi?
- Where does sine come from? [1/6/1995]
Who was the inventor of Sine? And when did he/she discover it? Also, how
did he/she do it?
- Who Invented Algebra? [06/07/2004]
Who invented Algebra?
- Who Invented Binary? [05/07/2000]
Who invented the binary system of numbers and when was it developed?
- Who was Hero (or Heron)? [11/12/1997]
I have been trying to find information on the Greek mathematician Hero.
- Why Are the Numbers on a Dartboard Where They Are? [03/09/2004]
The way that the numbers 1 to 20 are arranged on a standard dart board
at first seems to be random, but are they placed in such a way as to
encourage accuracy, i.e., so that missing a high number results in
hitting a low number?
- Why b for Intercept? [10/16/2003]
In the slope-intercept formula, y = mx + b, why is 'b' used to
represent the y-intercept?
- Why Does 1+1=2? [2/28/1995]
Nobody that I ask has been able to answer that question with an
explanation. Notice the word WHY, not HOW.
- Why Do We Need to Study Rational Numbers? [04/22/2008]
My students want to know why they need to know what rational numbers
are and what use they have in the real world.
- Why Is a Circle 360 Degrees? [07/01/1998]
Why is a circle defined as 360 degrees?
- Why m for slope? [11/9/1994]
My class wants me to ask you why the letter m was selected to represent
- Why Straightedge and Compass Only? [10/02/2002]
My geometry students want to know why constructions can only be done
using a straightedge and a compass.
- Why x and y? [11/30/1994]
Can Dr. Math tell me where we get x and y?
- Women in Mathematics [3/6/1996]
Would someone answer questions from eleventh grade girls about being a
- You Can't Trisect an Angle [7/16/1996]
Who proved you can't trisect an angle?