The CAS Registry Mumber 56192-71-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,6,1,9 and 2 respectively; the second part has 2 digits, 7 and 1 respectively. Calculate Digit Verification of CAS Registry Number 56192-71: (7*5)+(6*6)+(5*1)+(4*9)+(3*2)+(2*7)+(1*1)=133 133 % 10 = 3 So 56192-71-3 is a valid CAS Registry Number.