The CAS Registry Mumber 56059-63-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,6,0,5 and 9 respectively; the second part has 2 digits, 6 and 3 respectively. Calculate Digit Verification of CAS Registry Number 56059-63: (7*5)+(6*6)+(5*0)+(4*5)+(3*9)+(2*6)+(1*3)=133 133 % 10 = 3 So 56059-63-3 is a valid CAS Registry Number.