The CAS Registry Mumber 1240611-45-3 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,2,4,0,6,1 and 1 respectively; the second part has 2 digits, 4 and 5 respectively. Calculate Digit Verification of CAS Registry Number 1240611-45: (9*1)+(8*2)+(7*4)+(6*0)+(5*6)+(4*1)+(3*1)+(2*4)+(1*5)=103 103 % 10 = 3 So 1240611-45-3 is a valid CAS Registry Number.