The CAS Registry Mumber 82298-71-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,2,2,9 and 8 respectively; the second part has 2 digits, 7 and 1 respectively. Calculate Digit Verification of CAS Registry Number 82298-71: (7*8)+(6*2)+(5*2)+(4*9)+(3*8)+(2*7)+(1*1)=153 153 % 10 = 3 So 82298-71-3 is a valid CAS Registry Number.