How many three digit even numbers M can be formed that are divisible by 9 such that both M and M^2 have the same units digits?	Choose the correct choice from the following answers.
A) 20
B) 21
C) 22
D) 23
E) 24
For an even number to have the same units digit as its square, it must have the units digit of 0 (0^2 = 0) or 6 (6^2 = 6). Thus the units digit of M must be 0 or 6.   For a number to be divisible by 9, the sum of its digit must be divisible by 9.   If the units digit of M is 0, then M could be:   900;   810, 180;   720, 270;   630, 360;   540, 450;   990.   10 numbers.   If the units digit of M is 0, then M could be:   306;   216, 126;   936, 396;   846, 486;   756, 576;   666.   10 numbers.   Total = 10 + 10= 
<gadget id="calculator">10 + 10</gadget>
<output>20</output>
20.   20nswer: 20.
<result>A</result>
How many three digit even numbers M can be formed that are divisible by 9 such that both M and M^2 have the same units digits?