The CAS Registry Mumber 74022-41-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,4,0,2 and 2 respectively; the second part has 2 digits, 4 and 1 respectively. Calculate Digit Verification of CAS Registry Number 74022-41: (7*7)+(6*4)+(5*0)+(4*2)+(3*2)+(2*4)+(1*1)=96 96 % 10 = 6 So 74022-41-6 is a valid CAS Registry Number.