The CAS Registry Mumber 102152-62-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,2,1,5 and 2 respectively; the second part has 2 digits, 6 and 2 respectively. Calculate Digit Verification of CAS Registry Number 102152-62: (8*1)+(7*0)+(6*2)+(5*1)+(4*5)+(3*2)+(2*6)+(1*2)=65 65 % 10 = 5 So 102152-62-5 is a valid CAS Registry Number.