ND connects numbers with certain expressions which require numerical determiners:
+-ND--+-Yt-+ | | | I saw him three weeks ago
Also "The store is FIVE MILES away", "FIFTY PERCENT of them were women", "THREE OTHER people are coming", "These are the TWO BIGGEST buildings in the city". In each of these cases, the word on the right of the link - not the number - is used to link the word to the rest of the sentence. ND is also used to connect numbers to the percent sign "%"; this can then be used as a noun-phrase.
Numbers can also be used to modify the word "more", when it is acting as a plural determiner or noun: "Three more are coming", "Three more people are coming", "*Three more money is needed". Thus "more" has ND- optionally conjoined with its plural-determiner and plural-noun connectors.
Notice that ND is not used for ordinary noun-phrase number expressions: "Fifty people came to the party", "Fifty came to the party". For these purposes, numbers have ordinary plural determiner (Dmcn) and noun (S+/O-/J-) connectors. ND+ is only used when a numerical determiner is required:
I saw him three weeks ago *I saw him the weeks ago *I saw him Jane's weeks ago These are the two biggest buildings *These are the some biggest buildings(Note: The above statement is no longer entirely relevant: the Dmcn connector is strict enough that it is essentially interchangable with ND, and can thus be used to for linkages that require a numerical determiner. Some future version of Link-Grammar may make one or the other obsolete.)
ND+ on numbers is directly disjoined with the plural determiner and noun-phrase connectors, and conjoined with other connectors like NN- and EN-, used in building larger number expressions:
+-----EN-----+ | +--NN--+--ND--+ | | | | I saw him about fifty million years agoGrammar Documentation Page.