The CAS Registry Mumber 138150-36-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,8,1,5 and 0 respectively; the second part has 2 digits, 3 and 6 respectively. Calculate Digit Verification of CAS Registry Number 138150-36: (8*1)+(7*3)+(6*8)+(5*1)+(4*5)+(3*0)+(2*3)+(1*6)=114 114 % 10 = 4 So 138150-36-4 is a valid CAS Registry Number.