I just revisited this & managed to resolve the issue.

For some reason, manual casting is required on the online compiler.
I had to change the lines that use math to:

if int( float(x) % y ) == z
int( math.floor( float(x) / y ) )
int( math.ceil( float(x) / y ) )

Does anyone know why casting is required to be explicit on the online compiler, when implicit casting works fine on an actual native compiler?

the test values include negative integers. make sure your conditional logic takes that into consideration.