The CAS Registry Mumber 376-58-9 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 3,7 and 6 respectively; the second part has 2 digits, 5 and 8 respectively. Calculate Digit Verification of CAS Registry Number 376-58: (5*3)+(4*7)+(3*6)+(2*5)+(1*8)=79 79 % 10 = 9 So 376-58-9 is a valid CAS Registry Number.