The CAS Registry Mumber 84681-44-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,4,6,8 and 1 respectively; the second part has 2 digits, 4 and 4 respectively. Calculate Digit Verification of CAS Registry Number 84681-44: (7*8)+(6*4)+(5*6)+(4*8)+(3*1)+(2*4)+(1*4)=157 157 % 10 = 7 So 84681-44-7 is a valid CAS Registry Number.