The CAS Registry Mumber 76893-58-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,6,8,9 and 3 respectively; the second part has 2 digits, 5 and 8 respectively. Calculate Digit Verification of CAS Registry Number 76893-58: (7*7)+(6*6)+(5*8)+(4*9)+(3*3)+(2*5)+(1*8)=188 188 % 10 = 8 So 76893-58-8 is a valid CAS Registry Number.