The CAS Registry Mumber 94009-78-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,4,0,0 and 9 respectively; the second part has 2 digits, 7 and 8 respectively. Calculate Digit Verification of CAS Registry Number 94009-78: (7*9)+(6*4)+(5*0)+(4*0)+(3*9)+(2*7)+(1*8)=136 136 % 10 = 6 So 94009-78-6 is a valid CAS Registry Number.