The CAS Registry Mumber 74022-38-1 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, 3 and 8 respectively. Calculate Digit Verification of CAS Registry Number 74022-38: (7*7)+(6*4)+(5*0)+(4*2)+(3*2)+(2*3)+(1*8)=101 101 % 10 = 1 So 74022-38-1 is a valid CAS Registry Number.