MathDB
Units Digit

Source:

June 27, 2011

Problem Statement

Which of the following could not be the unit's digit [one's digit] of the square of a whole number?
(A) 1(B) 4(C) 5(D) 6(E) 8 \text{(A)}\ 1\qquad\text{(B)}\ 4\qquad\text{(C)}\ 5\qquad\text{(D)}\ 6\qquad\text{(E)}\ 8