# Thread: Fractions in fibonacci series

1. ## Fractions in fibonacci series

i've been sitting here for 2 hours searching through info sites
and forums getting absolutely nothing out of it. its a simple
problem i have. how to add fractions in c:

where a/b + c/d == x/y

can someone point me in the right direction?

2. You treat fractions as ordered pairs of integers, and reduce them to lowest terms if they aren't already, using the Euclidean algorithm

http://en.wikipedia.org/wiki/Euclidean_algorithm

to compute the GCD of the numerator and denominator and then divide both by it. In the case of adding fractions, use the formula

a/b + c/d == (ad + bc)/bd

followed by reduction to lowest terms as described above.

3. You better try again: That formula does not work for the following two fractions of adding 1/3 and 1/5. According to the formula above, this would be equivalent to 3/5, whereas the real answer is 8/15. Or is my arithmetic that bad??

4. Yes, your arithmetic is bad (1 * 5 + 1 * 3)/(3 * 5) == 8 / 15

If you tried it programmatically then a / b * c != a / (b * c) although the parenthesis should not be required by human conventions (multiplication has higher precedence in algebraic notation?)

5. mea culpa!!