The CAS Registry Mumber 772306-42-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 7,7,2,3,0 and 6 respectively; the second part has 2 digits, 4 and 2 respectively. Calculate Digit Verification of CAS Registry Number 772306-42: (8*7)+(7*7)+(6*2)+(5*3)+(4*0)+(3*6)+(2*4)+(1*2)=160 160 % 10 = 0 So 772306-42-0 is a valid CAS Registry Number.