The CAS Registry Mumber 612042-13-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 6,1,2,0,4 and 2 respectively; the second part has 2 digits, 1 and 3 respectively. Calculate Digit Verification of CAS Registry Number 612042-13: (8*6)+(7*1)+(6*2)+(5*0)+(4*4)+(3*2)+(2*1)+(1*3)=94 94 % 10 = 4 So 612042-13-4 is a valid CAS Registry Number.