In the following sentence:
If I understand it correctly, 张 means 一张 but 一 is omitted here.
Also, if you want to mean it in plural (i.e. buy multiple lottery tickets), the sentence should be the following.
Now, can I also omit 张 as well, to make the sentence the following:
In this case, does the sentence mean singular, plural, or both (which makes the meaning dependent on context)? Or is the sentence invalid grammartically in the first place?