The CAS Registry Mumber 159406-70-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,5,9,4,0 and 6 respectively; the second part has 2 digits, 7 and 0 respectively. Calculate Digit Verification of CAS Registry Number 159406-70: (8*1)+(7*5)+(6*9)+(5*4)+(4*0)+(3*6)+(2*7)+(1*0)=149 149 % 10 = 9 So 159406-70-9 is a valid CAS Registry Number.