The CAS Registry Mumber 1860-98-6 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,8,6 and 0 respectively; the second part has 2 digits, 9 and 8 respectively. Calculate Digit Verification of CAS Registry Number 1860-98: (6*1)+(5*8)+(4*6)+(3*0)+(2*9)+(1*8)=96 96 % 10 = 6 So 1860-98-6 is a valid CAS Registry Number.