The CAS Registry Mumber 77045-38-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,7,0,4 and 5 respectively; the second part has 2 digits, 3 and 8 respectively. Calculate Digit Verification of CAS Registry Number 77045-38: (7*7)+(6*7)+(5*0)+(4*4)+(3*5)+(2*3)+(1*8)=136 136 % 10 = 6 So 77045-38-6 is a valid CAS Registry Number.