python 3.x:
def carries (a, b):
return (a%10 + b%10)//10 + carries (a//10, b//10) if a else 0
is cleaner, but may execute slower than:
def carries (a, b):
return 0 if not a else (a%10 + b%10)//10 + carries (a//10, b//10)
or
def test (a, b):
if a: return (a%10 + b%10)//10 + carries (a//10, b//10)
return 0