The CAS Registry Mumber 100241-93-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,0,2,4 and 1 respectively; the second part has 2 digits, 9 and 3 respectively. Calculate Digit Verification of CAS Registry Number 100241-93: (8*1)+(7*0)+(6*0)+(5*2)+(4*4)+(3*1)+(2*9)+(1*3)=58 58 % 10 = 8 So 100241-93-8 is a valid CAS Registry Number.