The CAS Registry Mumber 78282-38-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,8,2,8 and 2 respectively; the second part has 2 digits, 3 and 8 respectively. Calculate Digit Verification of CAS Registry Number 78282-38: (7*7)+(6*8)+(5*2)+(4*8)+(3*2)+(2*3)+(1*8)=159 159 % 10 = 9 So 78282-38-9 is a valid CAS Registry Number.