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

[EX Q]: Roaches have two forewings and _ hind wings.
[EX A]: two

[EX Q]: Indoor cats live _ times as long as outdoor cats.
[EX A]: three

[EX Q]: Permanent teeth emerge at about three to _ months of age.
[EX A]:
four