The CAS Registry Mumber 43076-17-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 4,3,0,7 and 6 respectively; the second part has 2 digits, 1 and 7 respectively. Calculate Digit Verification of CAS Registry Number 43076-17: (7*4)+(6*3)+(5*0)+(4*7)+(3*6)+(2*1)+(1*7)=101 101 % 10 = 1 So 43076-17-1 is a valid CAS Registry Number.