10!=3628800

```
from fractions import gcd
class Solution(object):
def fractionAddition(self, expression):
"""
:type expression: str
:rtype: str
"""
# exp = ''.join([('+' if c=='-' else '') + c for c in expression])
exp = expression.replace('-', '+-') # Thanks ManuelP. This is more clear than the above.
# print exp
exp = exp.split('+')
# print exp
a = [(int(s.split('/')[0])*3628800//int(s.split('/')[1])) if s else 0 for s in exp]
# print a
s = sum(a)
b = 3628800
if a==0:
return '0/1'
g = gcd(s,b)
return str(s//g) + '/' + str(b//g)
```