The CAS Registry Mumber 60556-93-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,0,5,5 and 6 respectively; the second part has 2 digits, 9 and 3 respectively. Calculate Digit Verification of CAS Registry Number 60556-93: (7*6)+(6*0)+(5*5)+(4*5)+(3*6)+(2*9)+(1*3)=126 126 % 10 = 6 So 60556-93-6 is a valid CAS Registry Number.