Most of the Hong Kong population knows English (if not fluently, they know what you're saying!). It's important to know the numbers, since they are very handy when bargaining in the markets. You have a higher chance of getting a lower price if you speak their language. Also remember, more than half of the Hong Kong population speaks CANTONESE and not MANDARIN which is spoken mostly in the mainland of China.

1 - "Yat"

2 - "e" or "yee"

3 - "Saam" or "sam"

4 - "Say"

5 - "Um" or "Mm"

6 - "Lok"

7 - "Chaat" or "Chet"

8 - "Paat" or "Bat" (t is a cross between the t and a d)

9 - "Caw" or "Gow"

10 - "Sub" or "Sat" (as in "hat")

For higher numbers like  21 it  would be 2-10-1 so - "e"-"sub"-"yat"

45 would be 4-10-5 so - "say" - "sub" - "um"

When you reach the hundreds they use "paa man",  so 100 is "e" "paa man"

400 is "say" "paa man"