The CAS Registry Mumber 58350-74-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,8,3,5 and 0 respectively; the second part has 2 digits, 7 and 4 respectively. Calculate Digit Verification of CAS Registry Number 58350-74: (7*5)+(6*8)+(5*3)+(4*5)+(3*0)+(2*7)+(1*4)=136 136 % 10 = 6 So 58350-74-6 is a valid CAS Registry Number.