True. Whole Numbers can be used as a element as well as natural numbers.
The term "natural number," according to Wolfram MathWorld, refers either to a member of the set of positive integers 1, 2, 3, ... or to the set of nonnegative integers 0, 1, 2, 3, .... Regrettably, there seems to be no general agreement about whether to include 0 in the set of natural numbers. In fact, Ribenboim (1996) states "Let P be a set of natural numbers; whenever convenient, it may be assumed that 0 in P."
The set of natural numbers (whichever definition is adopted) is denoted N.
Due to lack of standard terminology, the following terms and notations are recommended in preference to "counting number," "natural number," and "whole number."
Of interest, check out these 10 Math Study Tips That Will Make You a Better Student shared by GetCollegeCredit.com.