The CAS Registry Mumber 564483-42-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 5,6,4,4,8 and 3 respectively; the second part has 2 digits, 4 and 2 respectively. Calculate Digit Verification of CAS Registry Number 564483-42: (8*5)+(7*6)+(6*4)+(5*4)+(4*8)+(3*3)+(2*4)+(1*2)=177 177 % 10 = 7 So 564483-42-7 is a valid CAS Registry Number.