The CAS Registry Mumber 120876-33-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,0,8,7 and 6 respectively; the second part has 2 digits, 3 and 3 respectively. Calculate Digit Verification of CAS Registry Number 120876-33: (8*1)+(7*2)+(6*0)+(5*8)+(4*7)+(3*6)+(2*3)+(1*3)=117 117 % 10 = 7 So 120876-33-7 is a valid CAS Registry Number.