The CAS Registry Mumber 207400-69-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 2,0,7,4,0 and 0 respectively; the second part has 2 digits, 6 and 9 respectively. Calculate Digit Verification of CAS Registry Number 207400-69: (8*2)+(7*0)+(6*7)+(5*4)+(4*0)+(3*0)+(2*6)+(1*9)=99 99 % 10 = 9 So 207400-69-9 is a valid CAS Registry Number.