mấy

Etymology
From.

Determiner

 * 1) some, an indefinite quantity greater than one

Usage notes

 * Colloquially, mấy often replaces and  as plural marker in many situations, but in formal writing, it rarely ever takes that role.
 * Plural marking is not always grammatically required in Vietnamese like in many Indo-European languages and can be omitted in many situations.
 * Sometimes deliberately spelled to convey informality on the Internet although the word is rarely (if ever) pronounced as such in real life.

Adverb

 * 1) how much, how many