The CAS Registry Mumber 30232-71-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,0,2,3 and 2 respectively; the second part has 2 digits, 7 and 1 respectively. Calculate Digit Verification of CAS Registry Number 30232-71: (7*3)+(6*0)+(5*2)+(4*3)+(3*2)+(2*7)+(1*1)=64 64 % 10 = 4 So 30232-71-4 is a valid CAS Registry Number.