The CAS Registry Mumber 146830-42-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,6,8,3 and 0 respectively; the second part has 2 digits, 4 and 2 respectively. Calculate Digit Verification of CAS Registry Number 146830-42: (8*1)+(7*4)+(6*6)+(5*8)+(4*3)+(3*0)+(2*4)+(1*2)=134 134 % 10 = 4 So 146830-42-4 is a valid CAS Registry Number.