Posted by Eleonora on Tuesday, September 8, 2009 at 10:52pm.
Is .121221222122221... (the pattern in this number continues forever) a rational number or irrational number? Why?
(my research is listed in a previous question post, but I'm stuck!!! Please help!) :)

Math  MathMate, Tuesday, September 8, 2009 at 11:07pm
Each term 0.12, 0.00122, 0.000001222, 0.00000000012222, ...
is a rational number. When continued forever and added together, it does not have to be a rational number.
Another example:
1, 1/3, 1/5, 1/7, 1/9, ... are all rational numbers.
If we look at the sum
S = 1  1/3 + 1/5  1/7 + 1/9  ....
S equals π/4, a known irrational number.
In fact, a nonrecurring decimal number is considered an irrational number.
See:
http://en.wikipedia.org/wiki/Irrational_number 
Math  camy, Wednesday, September 9, 2009 at 1:00am
you have to put in the division,addition,sub., or whatever to answer this...(44,8,74,21,4)=10

Math  MathMate, Wednesday, September 9, 2009 at 7:41am
Camy,
It is not a good idea to piggyback a question on someone else's question. It may get ignored or overlooked.
As there are no replies yet, I suggest you repost the question as a new thread.
Thank you.