The CAS Registry Mumber 190910-30-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,9,0,9,1 and 0 respectively; the second part has 2 digits, 3 and 0 respectively. Calculate Digit Verification of CAS Registry Number 190910-30: (8*1)+(7*9)+(6*0)+(5*9)+(4*1)+(3*0)+(2*3)+(1*0)=126 126 % 10 = 6 So 190910-30-6 is a valid CAS Registry Number.