The CAS Registry Mumber 103518-37-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,3,5,1 and 8 respectively; the second part has 2 digits, 3 and 7 respectively. Calculate Digit Verification of CAS Registry Number 103518-37: (8*1)+(7*0)+(6*3)+(5*5)+(4*1)+(3*8)+(2*3)+(1*7)=92 92 % 10 = 2 So 103518-37-2 is a valid CAS Registry Number.