The CAS Registry Mumber 60640-76-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,0,6,4 and 0 respectively; the second part has 2 digits, 7 and 6 respectively. Calculate Digit Verification of CAS Registry Number 60640-76: (7*6)+(6*0)+(5*6)+(4*4)+(3*0)+(2*7)+(1*6)=108 108 % 10 = 8 So 60640-76-8 is a valid CAS Registry Number.