The CAS Registry Mumber 100045-15-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,0,0,4 and 5 respectively; the second part has 2 digits, 1 and 5 respectively. Calculate Digit Verification of CAS Registry Number 100045-15: (8*1)+(7*0)+(6*0)+(5*0)+(4*4)+(3*5)+(2*1)+(1*5)=46 46 % 10 = 6 So 100045-15-6 is a valid CAS Registry Number.