How do we write a fraction of numerator as the sum of three unit fractions ?

2 answers

bogus
Are you talking about "Egyptian Fractions" ?
which says, that every proper fraction can be expressed as a sum of
fractions with a numerator of 1.
e.g. 17/22 = 1/2 + 1/4 +1/44
e.g 4/5 = 1/2 + 1/5 + 1/10

Here is a good treatment of the subject:
http://www.maths.surrey.ac.uk/hosted-sites/R.Knott/Fractions/egyptian.html#section6.1.1

I found a simple applet that will even find them for you
http://www.calcul.com/show/calculator/egyptian-fraction?n=7&d=12