The CAS Registry Mumber 140659-91-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,0,6,5 and 9 respectively; the second part has 2 digits, 9 and 1 respectively. Calculate Digit Verification of CAS Registry Number 140659-91: (8*1)+(7*4)+(6*0)+(5*6)+(4*5)+(3*9)+(2*9)+(1*1)=132 132 % 10 = 2 So 140659-91-2 is a valid CAS Registry Number.