In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

[EX Q]: Trees can also be air layered but air layering usually takes four to _ months to be successful.
[EX A]: six

[EX Q]: Some dentists prefer using the oral rinse for _ to five days at a time.
[EX A]: three

[EX Q]: Chronic infections cause about _ percent of cancer cases, mostly in developing countries.
[EX A]:
nine