The CAS Registry Mumber 207234-04-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 2,0,7,2,3 and 4 respectively; the second part has 2 digits, 0 and 4 respectively. Calculate Digit Verification of CAS Registry Number 207234-04: (8*2)+(7*0)+(6*7)+(5*2)+(4*3)+(3*4)+(2*0)+(1*4)=96 96 % 10 = 6 So 207234-04-6 is a valid CAS Registry Number.