The CAS Registry Mumber 76209-60-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,6,2,0 and 9 respectively; the second part has 2 digits, 6 and 0 respectively. Calculate Digit Verification of CAS Registry Number 76209-60: (7*7)+(6*6)+(5*2)+(4*0)+(3*9)+(2*6)+(1*0)=134 134 % 10 = 4 So 76209-60-4 is a valid CAS Registry Number.