# when the sum of some fractions be 1 prove if we want that the sum of some fractions be 1

when the sum of some fractions be $1$
prove if we want that the sum of some fractions be $1$ and the denominators of one of them is $d$ then another denominators should divisible by $d$ or $d$ should be divisible to another denominators.
It seems to be easy I tried to prove it.I first tried some cases.
$1=\frac{1}{2}+\frac{1}{3}+\frac{1}{6}$
Here we can see that $6$ is divisible by $3$. Also here $6$ is divisible by $2$ .But I want to prove one of the denominators but here two of them is possible.After trying a lot I cannot found any proofs.Any hints?
update1: the numerator should be prime
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plodno8n
As stated, the claim offered for proof is not true. For example:
$\frac{7}{12}+\frac{4}{15}+\frac{3}{20}=1$
An alternative, which avoids composite numerators:
$\frac{1}{12}+\frac{13}{15}+\frac{1}{20}=1$