number vs chalk up

number is a noun but chalk up is not a noun.

Word	Noun	Adjective	Verb	Adverb
number	Yes	No	Yes	No
chalk up	No	No	Yes	No

number (noun)	chalk up (noun)
an item of clothing
the property possessed by a sum or total or indefinite quantity of units or individuals
a clothing measurement
one of a series published periodically
a symbol used to represent a number
a numeral or string of numerals that is used for identification and may be attached to accounts, memberships, etc.
the number is used in calling a particular telephone
a short performance that is part of a longer program
the grammatical category for the forms of nouns and pronouns and verbs that are used depending on the number of entities involved (singular or dual or plural)
a numbered item in a series
a select company of people
a concept of quantity involving zero and units

number (verb)	chalk up (verb)
place a limit on the number of	keep score, as in games
determine the number or amount of	accumulate, sometimes as a debt
enumerate
give numbers to
add up in number or quantity
put into a group