See also the Dr. Math FAQ: 3D and higher Browse Middle School
Number Sense/About Numbers Stars indicate particularly
interesting answers or good places to begin browsing. Selected
answers to common questions: Multiplying by zero. Casting out
nines. Number facts from the Web. - Associative Property of
Multiplication and Grouping Symbols [10/22/2006] Does the
Associative Property of Multiplication make grouping symbols
unnecessary, since (a x b) x c = a x (b x c) = a x b x c? -
Averaging Ages [11/17/1999] What is the average age of these 4
children... - Babylonian Numbers [11/17/1999] Can you give me
information on the Babylonian number system? - Base 3
[10/24/2001] What is 2 + 2 in base three? - Base 5 [07/28/1997]
What is .23 in base 5? I know that 6 in base 5 is 11, 7 is 12
and so on. Would .23 be the same in base 5 as it is in base 10?
- Base of Roman Numerals [04/07/2001] What is the base of the
Roman numeral system, base 10 or base 5? - Bell Numbers
[10/15/1998] How are Bell numbers generated? What are th