Number + mo /number + shika + negative ( Genki II Chapter 14)

Number + も/Number + しか + negative

You can add も to the number word, when you want to say “as many as”

Ex: きのうのパーテイーには学生が二十人来ました。(As many as twenty students showed up at the party yesterday.)

You can add しか to the number word and turn the predicate into a negative when you want to say “as few as” or “only”

Ex: 私は日本語のじしょをいっさつしかもっていません。(I have only one Japanese dictionary.)