The objective of this research is wanting to count the number 2 2 matrices with entries in the field ℤ/pℤ, where p is prime, that have the additional property that both eigenvalues are also in ℤ/pℤ. It used the method of number theory with a quadratic formula to find the roots of the characteristic polynomial of a matrices. And the result is there are (p2/2)(p2 + 2p – 1) matrices for any p prime