It is very difficult to use the article "the". Would you take a look at the following sentence?
#1 Ten little children danced very well at the party.
Is #1 grammatically OK? Should I put "the" like #2?
Or are both OK but the meanings are different?
#2 The ten little children danced very well at the party.
Both are OK, but the meanings are different. In the first one, there may have been other children at the party. (Perhaps they didn't dance so well.) In the second sentence, the writer (or speaker) is referring to ten specific children. There may have been other children at the party, but we are only talking about these children.