The CAS Registry Mumber 102724-85-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,2,7,2 and 4 respectively; the second part has 2 digits, 8 and 5 respectively. Calculate Digit Verification of CAS Registry Number 102724-85: (8*1)+(7*0)+(6*2)+(5*7)+(4*2)+(3*4)+(2*8)+(1*5)=96 96 % 10 = 6 So 102724-85-6 is a valid CAS Registry Number.