
re: el fractions etc
Posted:
Aug 9, 1995 1:45 PM


>If I am thinking about this correctly then 1/4 divided by 3/5 can be >restated as 3/5 is 1/4 of what? So if you rebuild the rectangle so that >original 3/5 is now 1/4, the resulting rectangle is indeed 12/12, but here >I am stuck. If the tiles with x's were red and I build the rectangle I >still have only 3 red tiles or 3/12. > >What am I doing wrong? > >Looking forward to hearing from you:) > >Eileen >
Shouldn't 1/4 divided by 3/5 be restated as "1/4 is 3/5 of what"? Similarly, 8 divided by 2 could be restated as "8 is 2 of what?"
So, if 1/4 is 3/5 of "something", I would break 1/4 into three equal sections, so that each section would represent 1/5 of "something." But, breaking 1/4 into three equal sections results in sections that are 1/12. So, 3/12 is 3/5 of "something". So one twelfth is one fifth of "something". So, to find the whole "something", I would need two more fifths of "something" which would be two more twelfths added on to the three twelfths, giving me 5/12.
Whew!
Maybe I can show this using line segments:
 = 1/4, which is 3/5 of "something".
   = 3/12, which is 3/5 of "something".
     = 5/12 which is 5/5 of "something".
So,      = 5/12 = "something."
So,  = "something".
Norm Krumpe

