The CAS Registry Mumber 78749-62-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,8,7,4 and 9 respectively; the second part has 2 digits, 6 and 2 respectively. Calculate Digit Verification of CAS Registry Number 78749-62: (7*7)+(6*8)+(5*7)+(4*4)+(3*9)+(2*6)+(1*2)=189 189 % 10 = 9 So 78749-62-9 is a valid CAS Registry Number.