The CAS Registry Mumber 16652-47-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,6,6,5 and 2 respectively; the second part has 2 digits, 4 and 7 respectively. Calculate Digit Verification of CAS Registry Number 16652-47: (7*1)+(6*6)+(5*6)+(4*5)+(3*2)+(2*4)+(1*7)=114 114 % 10 = 4 So 16652-47-4 is a valid CAS Registry Number.