A/an answer is a punctuation mark used to show an important connection between words or parts of words.

Hyphen

The hyphen is a punctuation mark used to show the important connection between words or parts of words.  The hyphen is used to indicate compound adjectives placed before nouns such as “well-rounded individual.”  The hyphen is used to indicate fractions such as “three-fifths.”  The hyphen is used to indicate certain numbers as in “forty-two.” The hyphen is used with all “self” words such as “self-confident.”  And, the hyphen is used to break words at syllables if appearing at the end of a line on a page such as how a hyphen would be placed between the two “g’s” of “bigger” if bigger were to end a line and it needed to be split for the sake of space on a page.

All numbers divisible by 9 are also divisible by 3.

Step-by-step explanation:

Nine is basically just 3 3's.