The CAS Registry Mumber 76930-03-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,6,9,3 and 0 respectively; the second part has 2 digits, 0 and 3 respectively. Calculate Digit Verification of CAS Registry Number 76930-03: (7*7)+(6*6)+(5*9)+(4*3)+(3*0)+(2*0)+(1*3)=145 145 % 10 = 5 So 76930-03-5 is a valid CAS Registry Number.