Hi sluth had the same problem - not passing this challenge. I seem to have temporarily solved/passed it by starting to delete spaces inside the last section of the code: {font-size: 10px*$j;}.
Initially I had spaces after 10px and then another space after the multiplication(*) sign. At some point after deleting these two spaces it passed the test, and it passed using the word “through” instead of “to.”
I say temporarily because when I went back and changed to “1 to 6” it seemed to not pass again…put it back to “through” and passed again.