The CAS Registry Mumber 7622-04-0 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,6,2 and 2 respectively; the second part has 2 digits, 0 and 4 respectively. Calculate Digit Verification of CAS Registry Number 7622-04: (6*7)+(5*6)+(4*2)+(3*2)+(2*0)+(1*4)=90 90 % 10 = 0 So 7622-04-0 is a valid CAS Registry Number.