The CAS Registry Mumber 154954-44-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,5,4,9,5 and 4 respectively; the second part has 2 digits, 4 and 4 respectively. Calculate Digit Verification of CAS Registry Number 154954-44: (8*1)+(7*5)+(6*4)+(5*9)+(4*5)+(3*4)+(2*4)+(1*4)=156 156 % 10 = 6 So 154954-44-6 is a valid CAS Registry Number.