The CAS Registry Mumber 860520-94-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 8,6,0,5,2 and 0 respectively; the second part has 2 digits, 9 and 4 respectively. Calculate Digit Verification of CAS Registry Number 860520-94: (8*8)+(7*6)+(6*0)+(5*5)+(4*2)+(3*0)+(2*9)+(1*4)=161 161 % 10 = 1 So 860520-94-1 is a valid CAS Registry Number.