The CAS Registry Mumber 101836-33-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,1,8,3 and 6 respectively; the second part has 2 digits, 3 and 3 respectively. Calculate Digit Verification of CAS Registry Number 101836-33: (8*1)+(7*0)+(6*1)+(5*8)+(4*3)+(3*6)+(2*3)+(1*3)=93 93 % 10 = 3 So 101836-33-3 is a valid CAS Registry Number.