The CAS Registry Mumber 63240-97-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,3,2,4 and 0 respectively; the second part has 2 digits, 9 and 7 respectively. Calculate Digit Verification of CAS Registry Number 63240-97: (7*6)+(6*3)+(5*2)+(4*4)+(3*0)+(2*9)+(1*7)=111 111 % 10 = 1 So 63240-97-1 is a valid CAS Registry Number.