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

[EX Q]: Manatees swim two to _ miles per hour.
[EX A]: six

[EX Q]: Butterflies have _ pair of legs - each divided into five parts.
[EX A]: three

[EX Q]: Cartographers often divide scales into _ different categories.
[EX A]:
three