Python TypeError must be str not int

you need to cast int to str before concatenating. for that use str(temperature). Or you can print the same output using , if you don't want to convert like this.

print("the furnace is now",temperature , "degrees!")

Python comes with numerous ways of formatting strings:

New style .format(), which supports a rich formatting mini-language:

>>> temperature = 10
>>> print("the furnace is now {} degrees!".format(temperature))
the furnace is now 10 degrees!

Old style % format specifier:

>>> print("the furnace is now %d degrees!" % temperature)
the furnace is now 10 degrees!

In Py 3.6 using the new f"" format strings:

>>> print(f"the furnace is now {temperature} degrees!")
the furnace is now 10 degrees!

Or using print()s default separator:

>>> print("the furnace is now", temperature, "degrees!")
the furnace is now 10 degrees!

And least effectively, construct a new string by casting it to a str() and concatenating:

>>> print("the furnace is now " + str(temperature) + " degrees!")
the furnace is now 10 degrees!

Or join()ing it:

>>> print(' '.join(["the furnace is now", str(temperature), "degrees!"]))
the furnace is now 10 degrees!

print("the furnace is now " + str(temperature) + "degrees!")

cast it to str