The CAS Registry Mumber 58351-73-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,8,3,5 and 1 respectively; the second part has 2 digits, 7 and 3 respectively. Calculate Digit Verification of CAS Registry Number 58351-73: (7*5)+(6*8)+(5*3)+(4*5)+(3*1)+(2*7)+(1*3)=138 138 % 10 = 8 So 58351-73-8 is a valid CAS Registry Number.