The CAS Registry Mumber 58350-64-4 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, 6 and 4 respectively. Calculate Digit Verification of CAS Registry Number 58350-64: (7*5)+(6*8)+(5*3)+(4*5)+(3*0)+(2*6)+(1*4)=134 134 % 10 = 4 So 58350-64-4 is a valid CAS Registry Number.