The CAS Registry Mumber 80077-22-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,0,0,7 and 7 respectively; the second part has 2 digits, 2 and 2 respectively. Calculate Digit Verification of CAS Registry Number 80077-22: (7*8)+(6*0)+(5*0)+(4*7)+(3*7)+(2*2)+(1*2)=111 111 % 10 = 1 So 80077-22-1 is a valid CAS Registry Number.