I used a little critical thinking to deduce that the fraction must be of the form ab/bc = a/c where a does not equal c. After this, it was pretty easy to find the four fractions necessary.
#take a string of form (1, 2, a, b) and make it into one word or number of form 12ab
def str2num(n):
return ''.join(map(str, n))
# find: ab / bc = a / c
myset = []
for a in range(1, 10):
for b in range(1, 10):
for c in range(1, 10):
ab = float(str2num((a, b)))
bc = float(str2num((b, c)))
if ((ab / bc) == (float(a) / float(c))) and (ab != bc):
print ab, '/', bc
myset.append([a, c])
print myset