The CAS Registry Mumber 76054-98-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,6,0,5 and 4 respectively; the second part has 2 digits, 9 and 8 respectively. Calculate Digit Verification of CAS Registry Number 76054-98: (7*7)+(6*6)+(5*0)+(4*5)+(3*4)+(2*9)+(1*8)=143 143 % 10 = 3 So 76054-98-3 is a valid CAS Registry Number.