The CAS Registry Mumber 86970-90-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,6,9,7 and 0 respectively; the second part has 2 digits, 9 and 0 respectively. Calculate Digit Verification of CAS Registry Number 86970-90: (7*8)+(6*6)+(5*9)+(4*7)+(3*0)+(2*9)+(1*0)=183 183 % 10 = 3 So 86970-90-3 is a valid CAS Registry Number.