A number is one word. 125 dollars would be two words. You would never put “US” in – that would likely be automatically marked incorrect.
Similarly, a post code is one word. Really, it’s not even a word, but the test will never ask you for anything in addition to a post code. ie. the answer will never be “Bob’s post code – B7E 4R8”
Don’t overcomplicate things!
And remember, always write numerals, not the words. ie 38, not “thirty-eight”. This prevents spelling mistakes.