1.NounA ring whose elements are fractions whose numerators belong to a given commutative unital ring and whose denominators belong to a multiplicatively closed unital subset D of that given ring. Addition and multiplication of such fractions is defined just as for a field of fractions. A pair of fractions
a
/
b
{\displaystyle a/b}
and
c
/
d
{\displaystyle c/d}
are deemed equivalent if there is a member x of D such that
x
(
a
d
−
b
c
)
=
0
{\displaystyle x(ad-bc)=0}
.