Number. Like other collective nouns number may take
either a singular or a plural verb. Unlike most of them, it admits of a
simple and logical rule. When all that it is doing is forming part of a
composite plural subject, it should have a plural verb, as in:
A large number of people are coming today.
But when it is standing on its own legs as the subject it should have a singular verb, as in:
The number of people coming today is large.
The following are accordingly unidiomatic:
There is a number of applications, some of which were made before yours.
There is a large number of outstanding orders.
The
true subjects are not "a number" and "a large number" but
"a-number-of-applications" and "a-large-number-of-outstanding orders".
Of the following examples the first has a singular verb that should
be plural and the second a plural verb that should be singular.
There was also a number of conferences calling themselves peace conferences which had no real interest in peace.
The number of casualties in H.M.S. Amethyst are is thought to be about fifteen.
Those kind of things. The use of the plural
these or
those with the singular
kind or
so
FromTroubles With Number http://www.ourcivilisation.com/smartboard/shop/gowerse/complete/chap904.htm