The CAS Registry Mumber 58937-71-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,8,9,3 and 7 respectively; the second part has 2 digits, 7 and 1 respectively. Calculate Digit Verification of CAS Registry Number 58937-71: (7*5)+(6*8)+(5*9)+(4*3)+(3*7)+(2*7)+(1*1)=176 176 % 10 = 6 So 58937-71-6 is a valid CAS Registry Number.