Squirrels usually give birth to three or four in a litter, which is a number. The "three or four" in "three or four" is a number. The number is also called data, which explains the characteristics or reasons of things in terms of quantity. methods to make statements more accurate, more scientific, more specific and more convincing.

Squirrels usually give birth to three or four squirrels

Commonly used explanation methods include giving examples, giving actual examples to illustrate things, and making the things to be explained concrete and convenient for readers. Understand, this method of explanation is called giving examples.

In order to make the content of the explanation more substantial, specific and convincing, you can quote some literature, poetry, proverbs, famous quotes, etc. The scope of quotation is very wide.

Comparison is a method of comparing two things or phenomena of the same or different categories to illustrate the characteristics of things, so that readers can get specific and distinct impressions through comparison.