The CAS Registry Mumber 1186310-87-1 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,1,8,6,3,1 and 0 respectively; the second part has 2 digits, 8 and 7 respectively. Calculate Digit Verification of CAS Registry Number 1186310-87: (9*1)+(8*1)+(7*8)+(6*6)+(5*3)+(4*1)+(3*0)+(2*8)+(1*7)=151 151 % 10 = 1 So 1186310-87-1 is a valid CAS Registry Number.