In most situations, Japan uses all of the numbers available. However, due to different readings being available for the numbers, some have additional meanings which mean “death” or “suffer”.
This is a difficult concept that takes some explanation. The Japanese kanji system originated from China, and Chinese reading of these kanji came with it. Each character has multiple ways to read it, and in the case of “four”, it can be said either as “yon”(よん) or “shi”(シ).
“shi” also means “death” in Japanese, which is why hushing a Japanese person with “shhh” is quite serious, as it implies that you desire the silence that will come from their death.
Hospitals do not have 4th or 9th floors, as they do not want to be associated with death or suffering. Many parking lots also do not have 4th or 9th spots. Also, McDonald’s does not have a 9 piece Chicken McNugget set.
Although English does not carry the stigma that Japanese does, the students may show some unease when you have a listening activity and the CD is set to track 4, or the student needs to turn to page 9.
In these situations it is vital that you reassure the student that nothing bad will come of using those numbers in English. Teaching numbers in English should not be associated with negative experiences. Do your best to count without hesitation, and encourage the student to do so as well.