The CAS Registry Mumber 86847-50-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,6,8,4 and 7 respectively; the second part has 2 digits, 5 and 0 respectively. Calculate Digit Verification of CAS Registry Number 86847-50: (7*8)+(6*6)+(5*8)+(4*4)+(3*7)+(2*5)+(1*0)=179 179 % 10 = 9 So 86847-50-9 is a valid CAS Registry Number.