The CAS Registry Mumber 154942-22-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,5,4,9,4 and 2 respectively; the second part has 2 digits, 2 and 2 respectively. Calculate Digit Verification of CAS Registry Number 154942-22: (8*1)+(7*5)+(6*4)+(5*9)+(4*4)+(3*2)+(2*2)+(1*2)=140 140 % 10 = 0 So 154942-22-0 is a valid CAS Registry Number.