The CAS Registry Mumber 89747-54-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,9,7,4 and 7 respectively; the second part has 2 digits, 5 and 4 respectively. Calculate Digit Verification of CAS Registry Number 89747-54: (7*8)+(6*9)+(5*7)+(4*4)+(3*7)+(2*5)+(1*4)=196 196 % 10 = 6 So 89747-54-6 is a valid CAS Registry Number.