What does this rebus mean?
12356789 KOOL
Hint #1:
The answer has to do partly with the fact the 4 is MISSING, not JUST that the 4 is special itself.
Hint #2:
The phrase "look back" is correct and is in the answer. (Obviously it's not the entire answer though) You also have to be a bit creative with the whole number thing. Happy guessing!