more / less, fewer
When increasing the quantity of a noun, use the word "more."
When decreasing the quantity of a noun, choose between the words "less" or "fewer," depending on the type of noun it is. In this case, you need to consider if a noun is a count noun or a noncount noun. (Learn the differences between count and nouncount nouns in Blue Level Lesson Nineteen.)
Using "more" is fairly easy because you can use "more" with both count nouns and noncount nouns:
Choosing between "less" and "fewer" is not as easy. You really have to pay attention to the type of noun you are describing.
Generally, words that end in an "s" are plural count nouns. Words that don’t end in "s" but are considered plural are noncount nouns.
Watch this video:
Now take this quiz.